Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability.

I switched from PC to Mac a year ago, but now I am thinking of adding a Windows laptop. If I do, what kind of compatibility problem would I have? I would be using the laptop mostly to write, to send/receive email and to Web browse.

In the old days, there were compatibility problems, but most of those have gone away. Based on your simple predicted usage, I’d say that you should be fine. For instance, both Macs and PCs can interchangeably open and edit all of the major file types — JPG pictures, MP3 music, Microsoft Office documents, Adobe PDF files, etc. Email and instant messages can, of course, be exchanged between the two platforms, even if you are using different programs. And Macs understand Windows file extensions. Also, you can use both platforms simultaneously on the same home network to access the Internet.

In some cases, you might need different programs to open the same files on the two platforms. But even that obstacle has greatly diminished. For instance, programs like the Firefox and Safari Web browsers, Adobe Reader, iTunes, Microsoft Office, Google Earth, Picasa, Photoshop and many others come in native versions for both platforms that can handle the same files. And, of course, Web-based programs like Gmail and Yahoo Mail work on both. Sometimes, the same programs have different features and user interfaces on Windows and Macs, but I haven’t found these differences hard to master.

The biggest problems for average users are Quicken, whose Mac version is inferior and incompatible; Internet Explorer, which is no longer made for the Mac; and Microsoft Outlook, which is replaced on the Mac by a program called Entourage that is similar but uses a different file format. And networking can be tricky. In general, the Mac does a better job of seeing Windows PCs on a network than Windows does of seeing Macs.

I use Outlook Express for my email, and I store a lot of mail in local folders. Is there a simple way to back these up? If I buy a new computer, can they be transferred?

Yes. There are two methods. One is a manual method, which Microsoft explains in a detailed document at this Web site: support.microsoft.com/kb/270670.

The other, quicker, method is to obtain one of several utility programs that can back up your Outlook Express data and, in some cases, allow you to transfer it to another PC. I haven’t tested these in years, and thus can’t recommend one over another. But one example is a free program called Outlook Express Backup, which can be found at genie-soft.com/products/oeb. Another is a $40 program called Outlook Express Backup Wizard, which can be found at: outlook-express-backup.com.

Do you know of an iPhone GPS application that speaks directions? It would make the iPhone similar to a TomTom or Garvin GPS unit.

A: No, but Apple recently announced that, under its new 3.0 operating system for the iPhone, such programs will be possible. Several companies are believed to be working on them, and I expect them to be available later in the year. The reason none exist yet is partly legal, having to do with the licensing of the underlying maps.

• You can find Mossberg’s Mailbox, and my other columns, online free of charge at the new All Things Digital Web site, http://walt.allthingsd.com.

Does the new Palm Pre smart phone use the traditional Palm operating system and the many programs that have been written for it?

Palm’s Pre, which is due out later this year to compete with the iPhone and the BlackBerry, doesn’t use this older software, which was once the best smart-phone operating system, but has grown stale. It uses an entirely new operating system called the Palm webOS, which will have to attract developers willing to write new programs for it. It is a clean break from Palm’s previous hardware and software.

How does the Clickfree computer backup system you covered last week compare with Apple’s Time Machine or online backup services like Mozy or Carbonite?

Clickfree simplifies the chore of backing up files to an external hard disk. However, as I noted in the review, it doesn’t back up your whole hard disk, it doesn’t work automatically in the background, and it doesn’t create a backup physically distant from your computer.

Time Machine, which is built into the Macintosh operating system, automatically backs up your entire computer in the background and includes a very easy method for recovering files. It works with external hard disks. But it doesn’t work on Windows PCs, and it doesn’t create a remote backup over the Internet.

Mozy and Carbonite are online backup solutions. Their advantages are that they work unattended and create offsite backups. But they aren’t intended to back up an entire computer, they don’t create a local backup, and they carry service fees.

Does my 13-inch MacBook come with the capability to view PowerPoint files?

No. While Macs come out of the box with the ability to view and create files in the Microsoft Word and Adobe PDF formats, they don’t come with a PowerPoint viewer. In order to view (and create) PowerPoint files on a Mac, your best bet is to buy the Macintosh version of Microsoft Office, which includes PowerPoint itself. There are other methods as well. For instance, Apple’s own lower-priced iWork suite can also open PowerPoint files and create files in the PowerPoint format. And some Web-based office programs, like Google Docs, allow you to view PowerPoint files on Macs.

You can find Mossberg’s Mailbox, and my other columns, online free of charge at the new All Things Digital Web site, http://walt.allthingsd.com.

This week, I was swamped with questions about Apple’s hot new iPhone, so this is a special all-iPhone edition of Mossberg’s Mailbox.

Can you physically remove the included AT&T SIM card from the iPhone and replace it with another AT&T card or one from another wireless carrier?

Yes, and no. The SIM card, which carries the iPhone’s account information, can be removed by inserting a paper clip into a tiny hole at the top of the phone. However, Apple says that if you replace the included card with one from another carrier, like T-Mobile in the U.S., or Orange in Europe, the phone won’t work. According to Apple, some non-iPhone AT&T cards may work, but some may not.

It’s possible that hackers will figure out a way to override this lock on other carriers’ SIM cards. But, as of now, the iPhone will work only with AT&T. Even overseas, at least until Apple does deals with foreign partners, you won’t be able to use SIM cards from other carriers. The iPhone will work overseas, but you will have to roam with AT&T and pay high charges. For instance, according to an AT&T spokesman, if you make a call in Europe, it would cost $1.29 a minute. It would cost 99 cents a minute if you are on one of AT&T’s $5.99 per month international plans.

Since the iPhone battery is sealed in and can’t be easily replaced by the user, what happens when it dies? Will you have to buy a new iPhone?

No, but you will have to send the phone to Apple, or drop it off at an Apple store, to have the battery replaced. The battery is covered during the phone’s one-year warranty period. After that, replacing the battery costs $79, plus $6.95 for shipping, and takes three business days. Details are at apple.com/support/iphone/service/battery/. Some small companies may eventually offer to do this for less, or in less time, as they have for the iPod.

One twist: because a phone is a necessity, Apple is offering loaner iPhones for $29 while your phone’s battery is being replaced, or for the period of any other repair on the iPhone. You will have to switch the AT&T SIM card from your own phone to the loaner, and then back again. Details are at apple.com/support/iphone/service/faq.

In addition, Apple warns that all the data on your iPhone will be wiped out during a battery replacement, but notes that it can easily be restored by simply syncing again with the iTunes software on your computer once you get it back with a fresh battery. That’s because, whenever you sync your iPhone with iTunes, it backs up the data on the phone. You can also use this method to fill your loaner iPhone with your own data.

Can I use the iPhone via a Bluetooth wireless connection in my car? Can I use Bluetooth to transfer files or other information between the iPhone and a computer?

In my two-week test of the iPhone, I succeeded in connecting it without much trouble to the built-in audio system and microphone on a friend’s BMW. Almost instantly, the over 700 contacts I had on my test iPhone were displayed on the car’s dashboard screen and calls could be made and received through the iPhone.

However, this first iPhone can use Bluetooth to connect only with cars and with wireless phone headsets. It cannot use Bluetooth to transfer any data to or from a computer, to play music through stereo wireless headsets, or for any other purpose. As with many other missing features, Apple has the ability to add these to the iPhone through software updates delivered by synchronizing with your computer.

If the iPhone’s Web browser is so good, why can’t it play video on Web sites I visit?

At launch, the iPhone version of the Safari browser is missing some plug-ins needed for playing common types of Web videos. The most important of these is the plug-in for Adobe’s Flash technology. Apple says it plans to add that plug-in through an early software update, which I am guessing will occur within the next couple of months. However, a separate program included on the iPhone can play a limited selection of videos from YouTube, and the phone can play videos you purchase from Apple’s iTunes store, and certain videos you create yourself.

You have been critical in the past of some smartphones that don’t allow you to delete emails with a single click. Can the iPhone do this?

Yes. If you are reading an email and want to delete it, you just tap on a trash can icon at the bottom of the screen and the message disappears into the trash can with an animation that resembles water being poured through a funnel.

However, in the iPhone email program’s list view, it takes two steps to delete an email. You have to swipe across the message header or preview with your finger, and then tap the red delete button that appears. You can also press an “Edit” button, which allows you to delete emails in the list view, but this still requires two taps per message.

Unlike on a BlackBerry or Treo, the iPhone doesn’t allow you to delete whole groups of email en masse by date, or even to select large groups and then delete them en masse. This would be a good feature for Apple to add down the line.

Can you buy an iPhone and just use it to play music and videos like an iPod, and to surf the Web or get email over Wi-Fi, without signing up for an AT&T service contract?

No. None of the iPhone’s functions, except calling 911, will work unless the phone is covered by a two-year AT&T service contract, and has been “activated” by AT&T. That will cost you $60 a month at a minimum. If you are thinking of buying an iPhone, you should plan on being an AT&T customer, and if AT&T coverage is poor where you live, work and travel frequently, I advise you NOT to buy an iPhone.

You and many others have criticized AT&T’s EDGE data network, which the iPhone uses, as slow. You have noted that AT&T has a much faster data network. Can the iPhone be upgraded to use that faster network?

No, it can’t. This first edition of the iPhone can’t use any cellular network faster than EDGE, which is much, much slower than the fastest cellphone data networks available from AT&T, Verizon or Sprint. It can, however, use very fast Wi-Fi wireless networks, when you are in range of them.

Apple hasn’t said anything about future iPhone models, but I fully expect a future model that can use these faster cellular networks, which are usually called 3G networks. So, if this is very important to you, I’d suggest waiting to see if such an iPhone emerges. But I don’t expect this to happen anytime soon.

In the past few days, AT&T seems to have tweaked its EDGE network, at least in some locations, so it runs faster than it has in the past. In my own speed tests, around Washington, D.C., I have seen repeated speeds of around 150 kilobits per second, roughly 50% better than the 100 kbps I have seen with EDGE in the past. However, I have also recorded speeds as slow as 82 kbps. And, even the new, faster speeds are way below those of the faster American cellular data networks, which can easily reach 500 to 800 kbps on a phone.

How good is the iPhone’s To-Do list or Task function?

Awful — in the sense that it doesn’t exist. The phone does have a calendar, of course, which syncs with the most popular calendar programs on Windows and Macintosh computers. And it has a Notepad, which doesn’t sync with any program on any computer (though you can email notes to yourself and others). But it has no To-Do list function at all.

Write to Walter S. Mossberg at mossberg@wsj.com

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about using the Belkin Easy Transfer cable, moving files from a Mac to a PC and backing up a Mac with Parallels virtual machine software.

Last week, you advised using an Easy Transfer Cable to transfer files from a Windows XP computer to a new Windows Vista computer. But what about those of us still using Windows 98 who want to get a new Vista machine?

The Belkin Easy Transfer cable I discussed only works fully when the old PC is running the latest version of Windows XP, although it will work partially with Windows 2000. But there are other methods for people using older consumer versions of Windows, such as Windows 98 and Windows ME.

You can, of course, use a two-step process, copying your files to recordable CDs or to an external hard disk and then inserting the CDs into the Vista PC, or attaching the hard disk to it and moving the files over. You could also use a USB flash drive in the same manner. Or, if you are skilled at networking, you could move the files over a network.

However, there are also some cable solutions that will work with Windows 98 and Windows ME. For instance, the Tornado, the cable with the built-in manual file-copying software I discussed last week, works with versions of Windows back to the SE edition of Windows 98, though you need to install driver software for that version. More information is at www.thetornado.com.

Another product I reviewed last week, PCMover from LapLink, also works with older versions of Windows, albeit with different cables that LapLink sells, not the Easy Transfer cable. Information is at laplink.com. Another similar product that has worked for me in past tests is IntelliMover by Detto, at detto.com, which also comes with cables.

I am a Macintosh user and plan to buy a new Dell with Windows Vista. How can I move my programs and files from the old Mac to the new Dell?

Well, first of all, you can’t switch your Mac programs to the Dell. They won’t run on Windows. But nearly all of the common files used on a Mac, such as Microsoft Office documents, text files, pictures, songs and Adobe PDF files, will work fine on your Dell.

I don’t know of a simple, integrated cable-and-software solution for such a Mac-to-Windows migration. So you’ll likely have to use recordable CDs, or an external hard disk or USB flash drive. Just make sure to use drives that are formatted for Windows. Macs can read, and write to, such Windows drives, but Windows PCs can’t natively read, or write to, Mac-formatted drives.

I have a Mac running Windows via the Parallels virtual machine software. I am also running an older Windows PC, which I back up to an external disk drive. Can I plug the external drive into the Mac and copy the files into the Parallels environment?

Yes. A virtual Windows computer running on a Mac behaves just like a regular Windows computer, so you can indeed plug in an external hard disk and copy the files over. In addition, as I mentioned last week, the forthcoming new version of Parallels includes a utility called Transporter that will move the entire contents of a Windows PC into a virtual Windows machine running on a Mac. See parallels.com for details.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

• Write to Walter S. Mossberg at mossberg@wsj.com

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about deleting groups of emails on a Treo, eliminating unnecessary background programs and sending files from a Mac to a Windows PC.

How do I delete groups of email messages quickly on the Treo smartphone?

It depends on which Treo model you are using and which email program you are using. If it’s a Windows-based Treo, like the Treo 700w or 700wx, you can’t delete large groups of messages very quickly in the built-in email program. You have to manually select large groups of messages and then use the delete function. If it’s a Treo model that uses the Palm operating system, like the Treo 700p or the 650, it is usually possible to do this automatically with a few keystrokes, though the method varies depending on which email program you are using.

If you are using my favorite Treo email program, SnapperMail, on a Palm-based Treo, and you want to delete all or many of the messages in a mailbox, such as your inbox, you can do so with one hand and as few as three keystrokes. This “Purge” command allows you to delete all the messages, or only messages older than various periods of time you can set. You don’t have to use the stylus, or manually select any messages, or use two hands. You just press the menu button, the “T” key, and the center button on the navigation pad.

When I open the Windows Task Manager, I note that there are anywhere from 52 to 57 “processes” operating on my PC. I am sure this is slowing things down. However, the names of the programs are virtually impossible for a nontechie to understand so I don’t want to eliminate any of them for fear of causing major damage to the operating system. Short of calling a service technician, is there a way for me to find out which processes can be safely shutdown and/or eliminated?

This is one of the major banes of using Windows — every program and even some Web sites think it’s OK to install and run in the background all sorts of little, and not-so-little programs, which create the “processes” you are seeing. Some of them may even be spyware and adware. And, yes, they do slow down your computer.

Unfortunately, I don’t know of any quick, easy way a mainstream, nontechie user can tell which ones can be safely shut down. There are programs like Startup Cop that help you decide which unseen programs you should allow to launch when your computer starts, but they don’t necessarily cover stuff that launches after start-up. And there are Web sites, like processlibrary.com and answersthatwork.com, which let you look up a process to see what it does, but that is a laborious process. The latter Web site offers a $29 program called the Ultimate Troubleshooter for managing all these processes, but it’s pretty intimidating for a nontechie.

Antivirus and antispyware programs can shut down some malicious background processes, or stop them from loading in the first place. But many of the resource-draining “processes” you are finding may be from “legitimate” programs on your PC that simply want to hog the computer.

If I switch from Windows to a Macintosh, will my colleagues be able to read any Mac files I send them?

There is no such thing as a “Mac file.” The Macintosh today can create and read all the major standard types of files that Windows PCs use. For instance, photos in the common JPG format; music files in the common MP3 format; Adobe PDF files; text files; and many other types of files can simply be moved between Windows and Mac computers with no conversion necessary. Microsoft Office files, like Word, Excel and PowerPoint documents, can also be shared between the two platforms, without conversion, if you have the Office program suite on both ends. The Mac’s built-in email program, Apple Mail, even has a setting for sending “Windows Friendly” attachments.

There are some specific programs on both platforms that can create proprietary file types not easily opened, or opened at all, on the other platform. Most annoyingly, the Windows and Mac versions of Quicken don’t share a common file format. But now that the new Macs can also run Windows, you can always launch Windows on your Mac in a pinch to run a program that can handle some Windows-only file type.

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Because of the volume of email I receive, I can’t routinely answer individual questions by email, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about switching to a Web-based email service, viewing PDF files on Macs and antivirus programs that support Windows ME.

Q: I use an email address provided by my Internet service provider and access my email using Microsoft Outlook. I would like a more portable email address that isn’t tied to any one ISP, and an email program that is independent of any particular computer. What can you suggest?

The obvious answer is a Web-based email service that has a decent Web-based interface that can be accessed from any computer. There are lots of these, including Yahoo Mail, Microsoft’s Windows Live Mail (formerly Hotmail) and Google’s Gmail. I am not a fan of Gmail, which I believe has too many quirks and too few options for users to avoid them. Windows Live Mail is promising, but my favorite among these leading services is Yahoo Mail.

Q: I am thinking of switching to Apple, but I am wondering if Macs come with free Adobe Reader software, like some Windows computers do.

No, Macs don’t include Adobe Reader, which allows the viewing of PDF documents — but they don’t need it. The Mac operating system allows you to open and create PDF documents, right out of the box, without any additional software. If you get a PDF file as an email attachment, you can just double-click it and it opens. Even better, any program running on the Mac can save almost anything as a PDF file. For instance, you can save a Web page as a PDF file that can be opened in Adobe Reader on Windows. Adobe charges money for software that does that.

However, if you prefer Adobe Reader, there is a free Mac version, very similar to the Windows version, that you can download at www.adobe.com.

Q: Do you know of any antivirus programs that are continuing to support Windows ME in their newest versions?

The latest version of Grisoft’s very good AVG Anti-Virus program still works with the ancient Windows ME operating system, according to the company’s Web site, at www.grisoft.com.

Q: Last week, in answering a question about the speakerphone function on another Windows Mobile phone, you claimed that, on the Motorola Q, a multistep software process is needed to turn on the speakerphone. But isn’t that wrong? Isn’t there a hardware button that does that?

Yes, I erred when I wrote that. I just blanked on the hardware button, which I certainly knew about, having carried a Q for a couple of weeks while testing it. We have already run a formal correction, and I hereby apologize to Motorola for implying that the process was clumsy, when it’s simple.

* * *

Because of the volume of email I receive, I can’t routinely answer individual questions by email, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about Internet security fears, red-eye elimination in photos and software availability for Macs.

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

Are there any possible security dangers when a DSL modem is left on while the computer is turned off?

No, as long as it’s the only computer connected to the modem. The modem only fetches data from the Internet when a computer program, like a Web browser or email software, requests it to do so. If the computer is off, no such requests can be made, so no data, safe or unsafe, is being received. Similarly, if the computer is on but the modem is off, the computer isn’t connected to the Internet, and can’t receive any data, normal or malicious.

However, I feel compelled to note that, if you allow your Internet usage to be totally ruled by security fears, you may miss out on a lot. One of the great benefits of always-on broadband services like DSL is that your email flows in continuously; upgrades (including security upgrades) can be downloaded automatically, day or night; and you can take advantage of remote backup and file-synchronization services that work in the middle of the night.

I have a new Sony camera and need help editing my photos to eliminate red eye. I have small grandchildren who always have red eyes in my pictures. What software can I use to get rid of it?

Almost every photo software program I have tested has a red-eye elimination feature, and most are adequate. You just have to get the hang of it. If you have a Windows PC, try Google’s free Picasa program, or Adobe Photoshop Elements. On a Mac, you can use the built-in iPhoto software, or the Mac version of Photoshop Elements. You could also use a professional program like Photoshop, though that might be overkill.

I am thinking seriously that my next computer purchase will be an Apple. My question is: How prolific is the software that is written for Macs? I’m thinking of financial software like Quicken, but also the basic Office suite of products.

There are Mac versions of both Quicken and Microsoft Office. The latter can directly read and write to the same file formats as its Windows counterpart; the former cannot. Apple claims there are now thousands of software programs that run on the current Macs. So is there is a decent selection of software for general consumers.

However, there is vastly more software available for Windows, especially in certain categories like games, business software, databases and niche products for specific professions and hobbies. If you are likely to be satisfied with the main types of software — like office programs, Web browsers, email programs and multimedia players — you’ll be fine with the Mac. But if you are interested in any of these other categories, or in generally having the greatest selection, stick with Windows.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about finding low-cost DSL service, choosing video-editing software and transferring files from a Windows PC to a Mac.

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

Last week, you mentioned that DSL Internet service is available in the U.S. for $15 a month. I can’t find anything nearly that low. Can you elaborate?

Verizon, which is an Internet service provider operating in 28 states plus the District of Columbia and Puerto Rico, has an entry-level DSL plan for $14.95 a month. According to the Verizon Web site, this plan requires a one-year agreement, but it isn’t a teaser price that lasts for only a few months. You also get the first month free and they throw in the DSL modem. For this price, you get a DSL line that operates at speeds up to 768 kilobits per second for downloads and 128 kilobits per second for uploads. That’s more than 13 times the maximum download speed of a dial-up connection.

More info is at: www22.verizon.com/forhomedsl/channels/dsl/packages/.

I realize that this plan, or any Verizon plan, isn’t available in the other 22 states. And, I realize that, even where it is available, it may not be possible to get it at your house because of the technical limitations of DSL, which works well only within a certain distance from a phone company office. I also know that such service, at any price, is often unavailable in rural areas.

But, for tens of millions of people, this is a very inexpensive way to get broadband. It’s less than America Online charges for dial-up service.

A friend of mine is looking for some video-editing software to be used on a PC running Windows. What software would you recommend for this application?

I haven’t tested this category of software in a while, but any of the leading software packages should do. They include Pinnacle Studio Plus, Adobe Premiere Elements and Roxio Easy Media Creator. The first two are video-editing programs. The last includes a video-editing program, but it is a suite that also handles things like music and photos. Of the two video-only programs, Pinnacle’s is probably best for a novice user. It costs about $90.

I know the Macintosh can handle most common types of files used on Windows computers. But my question is more basic: if I switch to a Mac from Windows, how do I physically transfer my files?

If you buy your new Mac at an Apple store, Apple will do this job, or part of it, free. According to the Apple Web site, you can just bring the two computers to the store, and a “Genius” — Apple’s name for a tech support person in its stores — will move all the files in any folder you choose on your Windows machine onto your new Mac. Presumably, this would include the My Documents folder, which contains most of the data files on most Windows PCs. The “Genius” will also do this for $50 for people who bought their Macs elsewhere. There is some fine print to this deal. For details, see: www.apple.com/switch/howto/genius.html.

There are also numerous ways to do this yourself, depending on the capabilities of your Windows machine. You can copy the files from the old computer onto an external hard disk, or a USB thumb drive. You can burn them onto CDs or DVDs. You can copy them to the hard disk of an iPod, if you haven’t filled it up with music, and if you configure it for use as a disk drive.

Because the Mac can read Windows-formatted disk drives, you should be able to plug any of these devices into your new Mac, or insert the CDs or DVDs, and they should show up on the Mac’s desktop. Then, you can simply copy the files to folders of your choice on the Mac’s hard disk. You can also email files to yourself, or transfer them over a local network.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

In WordPerfect, it’s possible to sort paragraphs alphabetically. For example, in a bibliography you could rearrange the entries, which are short paragraphs, in alphabetical order, even if you didn’t enter them in that way. Is there a way to do this in Microsoft Word?

Yes, though Word makes the command a little hard to find. Just go to the Table menu and choose “Sort…” From its location, you would think this command sorts only entries in tables, but it also sorts paragraphs that aren’t in tables.

When you click on “Sort…” a little window will appear. Make sure the “Sort By” box in this window is set to “Paragraphs,” and the “Type” box is set to “Text.” You can choose to sort your paragraphs in ascending order (A to Z) or descending order (Z to A.)

By default, the command selects and sorts all your paragraphs. If you want to sort only some of them, select the ones you are targeting before you click on the command.

Lately I’ve been running antivirus, antispyware, and fix-it programs daily. Now I’m hearing that some viruses are a “necessary evil” to keep some programs running. Is that true?

No. By definition, a virus is a malicious piece of software that sneaks onto your computer to cause mischief or do real harm. I know of no legitimate program that in any way requires a virus to function. If you did have some program that required a true virus to operate, I would delete that program, because it would be, by definition, malicious software itself.

It’s possible, of course, that your antivirus program is mislabeling as a virus some piece of software you intentionally installed and that you need and want. But that’s a different matter. In that case, you could use the options in the security program to allow the misidentified program to live in peace. But you’d better be absolutely certain what it is, what it does, how you got it, and that you need it. Virus writers are always trying to outwit antivirus programs by creating viruses that pose as legitimate programs.

Early on in the digital photography era, at several seminars I attended, the speakers strongly recommended using a desktop Mac or PC as opposed to a laptop for processing digital images. Is this still the case or are laptops with similar power and memory equal to the task today?

I’m not sure what you mean by “processing” digital images. But if you are referring to organizing and editing images, most laptops sold today would do the job fine, whether they run Windows or the Macintosh operating system. They have enough power, memory and hard-disk capacity to handle the digital photo needs of mainstream consumers.

The exception might be a case where a professional photographer, or a very serious amateur, is doing extensive editing in Adobe Photoshop of hundreds or thousands of images — or the laptop is a low-end, lightly equipped model. In those cases, I’d advise using a costlier, well-equipped laptop, or a powerful desktop.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com