A: The built-in backup program in your iMacs, called Time Machine, doesn’t require Apple’s Time Capsule product to work. It will work with almost any brand of directly connected external hard disk.

For instance, I back up my home iMac to a Western Digital drive that’s connected to it via a cable.

As for hard-drive life, it’s my experience that many seem to die sooner or later, especially if they are used heavily. I don’t know if the ones inside the Time Capsule are especially fragile. But, in just the past six months, I’ve had an external hard disk from G-Tech die on me; seen an internal hard disk on my home Dell die for a second time; and discovered that the hard disk on my colleague’s MacBook died.

One way to protect against the failure of a local backup drive is to consider, in addition to using an external disk, backing up your data to an online backup service like Mozy, Carbonite or SugarSync.

My Dell has Microsoft Vista but I can upgrade free to the new Windows 7. However, I was told my antivirus software won’t be compatible and my email will change—the program will no longer be “Windows Mail.” What do you recommend?

A: I regard Windows 7 as much better than Vista, but you are correct that many antivirus programs will require upgrading and Windows Mail will go away during the upgrade. You’ll have to install a new email program, such as the very similar “Windows Live Mail,” which can import your messages. So, the question really is one of trade-offs. If you’re satisfied with Vista, and would rather not perform these program replacements, you should stand pat. If you don’t like Vista, and are anxious to replace it, then the hassles you describe could be worth it.

Will Office 2003 work with the new Windows 7 operating system?

A: Microsoft, which makes both products, says the answer is yes, though I haven’t tested it.

Is it possible that the Verizon Motorola Droid, which doesn’t work in Europe, could be turned into a “world phone” that could work on European cellphone networks via an app somebody might develop?

A: An app wouldn’t be able to do that for the current Verizon Droid. It’s a hardware issue.

Verizon’s Droid, like most Verizon phones, is built to run on a type of network called CDMA that isn’t used in Europe or most other countries outside the U.S., which use a network standard called GSM.

To run on these networks, the Droid, or any other current CDMA phone, would need an entirely different radio, or two radios, one for each type of network.

Verizon offers a handful of so-called “world phones,” which have both kinds of radios inside, but the Droid isn’t one of them. Motorola may well make a new model with two radios, or even a model with one radio that would work overseas, and I wouldn’t be surprised if it did so.

What could be done with an app is to allow the Droid to make so-called VOIP phone calls via the Internet.

In fact, while I haven’t checked, there may already be such an app for Android—the Droid’s operating system—that would do so. But, in many cases, making such Internet phone calls requires the user to be in range of a Wi-Fi network. Some carriers don’t allow such calls to be made over their cellular networks.

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

I have a PC with Windows XP, which I bought because my computer guru said to stay away from Vista. I read your column saying upgrading from XP to the new Windows 7 will be much more cumbersome than doing so from Windows Vista. So, what should I do now? Upgrade to Vista for a while so I can then move more smoothly to 7? Or wait, buy a separate Windows 7 computer in the fall, and just transfer my files and applications from the XP computer?

Putting budget considerations aside, I think the latter course would make more sense. The new machine with Windows 7 preloaded will probably give you smoother performance than one you upgraded twice to new operating systems in a matter of months. But, bear in mind that you will have to reinstall all your applications on the new Windows 7 computer, and that, depending on the terms of the applications’ licenses, you might even have to buy new copies. On the other hand, if you do the chain of upgrades, and don’t buy a new machine, you may be able to avoid this application problem, or at least much of it.

I appreciated your review of the Clickfree automatic backup drive. Does the backup it creates include the various folders and subfolders for data such as photos, or does it just create a huge single list?

The Clickfree software is primarily designed to back up, display and restore your files by their types — photos, music, text, email, spreadsheets, etc. Once it has performed a backup it lets you view and restore your files by these types. However, it will display the tree of all your folders and allow you to specify where it should search for these files. It also allows you to back up and restore entire folders, such as your My Documents folder, regardless of their contents. Detailed information, including a downloadable user manual, is available in the Support section of clickfree.com.

I am planning to buy one of the products you recently reviewed — a Western Digital My Book — and attach it directly to a port on my Internet router. Can I install antispyware and antivirus programs on the drive? If not, how will the data on this drive be protected?

Nothing is perfectly secure. The bad guys are clever, and you never say never. However, since this product isn’t an actual PC running Windows, viruses and spyware programs can’t likely run directly on it. Still, if one of your computers contains malicious software, and it can see the contents of the network drive, then the data on the drive could be endangered. I know of no way to install or run security programs on the drive. But the security software on your PC may protect the drive, if it is able to handle external drives across a network. Also, the firewall built into your network router will help. The product has some security measures built in, such as encrypting files when you use the optional feature that allows you to access the drive’s contents across the Internet.

• 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.

After reading your positive review, I downloaded Firefox 3.0, only to discover that some of my favorite add-ons, including a search toolbar, are incompatible. What can I do about this?

Wait. As I noted in the review, when major new versions of Firefox come out, it takes a while for some of the many add-ons for the browser to be updated so they are compatible with the new version. Because these are written by a very large number of different companies and individuals, the process will be gradual, and some will be updated more quickly than others.

As for search toolbars, like those from Google (GOOG) and Yahoo (YHOO), I doubt that most people still need them. When they first came out, these toolbars provided things the top browsers lacked: a permanent search box, pop-up blocking and a few other useful features. But all the major browsers now provide these things without requiring the installation of any external toolbar. The companies that make the toolbars can use them to sell advertising or attract you to their search engines. But, for many users today, they are redundant.

I don’t want to run antivirus software constantly, but I would like to periodically run a program that could scan my computer and remove viruses and the like. Does such a program exist?

Yes. Here’s one example. Microsoft (MSFT) makes a small, free program called the Malicious Software Removal Tool that looks for, and tries to remove, a limited number of the worst examples of malicious software. It can be downloaded at www.microsoft.com/security/malwareremove.

However, this isn’t a comprehensive antivirus program. Microsoft says it detects and removes only “specific, prevalent malicious software,” and advises that “You should also use up-to-date antivirus software to help protect your computer from other malicious software.”

I am in the market for a laptop. I was considering a Dell (DELL) or an H-P (HPQ) but have learned that Apples now run Windows. I have financial (Quicken) and other business files (Excel, Word and PowerPoint) that would need to be transferred to the new computer. Would this be possible on an Apple (AAPL)?

Yes, in the same ways you could transfer files from one Windows PC to another. For example, you could burn them to a CD or DVD, copy them to an external USB drive, or transfer them over a network or via the Internet. In fact, if you buy your Mac at an Apple retail store, the store’s staff will move your files over free, or for a modest fee, depending on which folders, and how many, you want transferred.

Once the files are on the Mac, you can either use native Mac programs to read and/or modify them, or you can install Windows and run your usual Windows programs to handle the files.

For instance, even if you never installed Windows on an Apple, your Excel, Word and PowerPoint files could be used in the Mac version of Microsoft Office. However, the Mac version of Quicken isn’t as compatible with the Windows version’s files. So, for Quicken, I suggest installing Windows on the Mac and running the Windows version of Quicken.

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

We are connected to Comcast (CMCSA) cable and use no antennas. Will we need one of the government-subsidized converter boxes next February?

Not if you are using a cable set-top box, like the vast majority of cable customers. If you are one of the minority of cable households whose TVs use an internal cable tuner, you may need a converter box. To be sure, contact your cable company or TV manufacturer.

In your laptop buying guide last week, you recommended buying a machine equipped for the “n” type Wi-Fi of wireless router. I was under the impression that this has not yet been standardized. Is that wrong?

The engineering committee that has been debating the standard for years has not yet completed its work, but the market has simply moved ahead on its own. This new, faster version of Wi-Fi is being built into routers, computers and other devices by nearly every major manufacturer. In my limited tests, I have found no compatibility problems, and it is backwards compatible with the older “g” and “b” standards.

Is the Mac immune to viruses? If not, do you have a recommendation of the type of antivirus software one should procure and load onto a Mac?

No personal computer or personal computer operating system of which I am aware is “immune” to viruses, spyware or other malicious software. That includes Apple’s (AAPL) Macintosh and its operating system, Mac OS X Leopard. Hackers have demonstrated the ability to invade the Mac. However, there are only a handful of viruses or other malicious programs for the Macintosh that have successfully spread beyond the lab. And these have harmed only a small number of actual users.

Of the well over 100,000 known viruses, spyware programs and other malicious software applications that are about in public, all but this handful are written to run on Microsoft (MSFT) Windows, and cannot operate on the Macintosh OS. For that reason, I don’t believe Macintosh owners need security software, unless they install and run Windows on their computers. If they do run Windows, Mac owners are well advised to purchase and install Windows security software to protect the Windows portion of the machine.

Having said that, I do not mean that Mac owners should be blind to security threats that don’t involve viruses or spyware. Just like Windows users, Mac users can succumb to what is called “social engineering” — scams and schemes that operate via email and Web sites that are often authored by crooks but made to look official. So, like Windows users, they must be on their guard.

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

Do I need antivirus or antispyware software on a Macintosh running the Leopard operating system?

The Macintosh isn’t inherently invulnerable to malicious software. In fact, last week it was reported that there is a new scam on the Web that can plant a malicious “Trojan horse” program on the Mac. However, this is a rare event. There have been practically no viruses, spyware or other malicious programs written for the Macintosh that have actually spread outside the laboratory.

For that reason, most Mac users don’t run security software, and security software companies don’t make much of an effort to sell it for Macs. I don’t believe it is necessary, so far, for all except the most paranoid (and those who run Windows on their Macs). In fact, freedom from the burdens of running and updating security software has been one of the Mac’s big advantages.

Even the new Trojan Horse apparently relies on tricking the user, rather than on sneaking through holes in the Mac operating system. According to reports, to get infected you must go to a pornography site, and agree to download a program allegedly needed to view the porn. Next, the Mac will require that you type in your administrator ID and password to complete the installation, thus agreeing to install the program a second time. If you do all that, you get a program that supposedly redirects your Web browser to bogus Web sites. My advice: even if you frequent porn sites, don’t agree to download any programs from them (that goes for Windows users as well).

Some interpret the appearance of this new Trojan Horse as a sign that the Mac’s increasing market share will begin to attract a flood of viruses and spyware, and that Mac users will soon have to start running security software. If it happens, and the threats are more insidious than the latest one, I will be ready to change my recommendation. But not yet.

In reply to a question last week, you mentioned that there are free security programs available for Windows. Could you please suggest where to download such alternatives?

There are a number of them, but ones that I like are free, basic antivirus and antispyware programs called AVG from a company called Grisoft, which also makes more elaborate security software. You can download these programs at free.grisoft.com/doc/5390/us/frt/0.

I don’t have Microsoft PowerPoint but I occasionally get PowerPoint files as email attachments. Somewhere I read that one can download a free PowerPoint program so you can read these files. Can you help me with this, please?

I don’t know of any free versions of PowerPoint, but Microsoft does offer a free program that will let you view, but not create or edit, PowerPoint files. You can download it here.

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

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

I currently spend about $50 to $60 per year for Norton Security software. Is this necessary when Windows XP has its own security built into the operating system?

Windows XP doesn’t include antivirus or antispyware programs, so you definitely need some sort of add-on security software. If you don’t want to pay for it, there are free alternatives available.

How do we determine when to purchase a new PC? Our current Dell is about five years old. I’m feeling a little worried because I have my music and photos on the computer and don’t want to lose them.

There’s no universal answer to your question. In general, I don’t believe people should replace computers that are working well for them just because they reach a certain age. On the other hand, five years is pretty old for a PC. At that age, the odds increase that the hard disk may develop problems, and that newer versions of the software you like will require hardware upgrades that may cost more than you want to invest in an older machine.

Assuming your Dell is working fine, that you aren’t a power user, and that your music and photo activities are simple and basic, there’s probably no urgent need to replace the PC. But, to assuage your concern about “losing” your pictures and music, you might back up those precious files to an external hard disk or an online backup service.

Last week, you compared the start-up time of Windows Vista to Apple’s new Leopard operating system, and found Vista to be much slower. But you used different laptops for each. What would the numbers be on the same Macintosh running the two operating systems?

I ran the tests again on a single computer, a fairly new Apple iMac, which can be started up, and restarted, in either Vista or Leopard. I used the Mac’s Boot Camp feature, in which only one operating system is running at a time, has its own dedicated portion of the hard disk and fully controls the hardware. The machine uses an Intel processor and other key components commonly found on Windows machines, and runs Windows just like a Dell or any standard Windows PC, without any involvement from the Mac operating system.

This Vista installation doesn’t include any of the speed-robbing trial software commonly included by PC makers, though it does have security software from Symantec. However, the test results were very similar — Leopard started and restarted much more quickly than Vista did.

In this simple test, I timed both operating systems from a cold start and a restart until the computer was fully ready for operation, with the hard disk quiet and the network connection established. The cold start, beginning with the computer completely off, took Leopard 46 seconds, but took Vista one minute and 42 seconds. A restart, beginning with the computer running an email program, the Firefox Web browser, and Microsoft Word, took one minute and two seconds for Leopard, and three minutes and 17 seconds for Vista.

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

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 Windows Vista complaints, using antivirus software when running Windows on a Mac, and transferring large files.

In various past columns, you have complained that Windows Vista boots slowly and that it is incompatible with some software and hardware. Is this situation improving?

Microsoft claims that neither complaint affects most users, and that the minority of cases where they do is being whittled down steadily. I expect that the incompatibility issues, at least, will diminish over time. But I am still receiving reader complaints about incompatibility, so I have to assume that this issue remains real, at least for some people. The slow start-up issue will be harder to cure, as it involves factors like add-on trial software, called craplets, that are beyond Microsoft’s control. Officials at a number of Windows PC makers tell me they are beginning to get the message that people hate craplets. But I am still observing slow boot times in new Vista PCs I test and still see plenty of craplets.

If I run Windows on a Mac, do I need two copies of antivirus software, one to run in the Windows environment, and one to run in the Mac operating system?

You need only one copy, to run in the Windows environment. Macs have essentially no virus problem, and thus don’t need antivirus software. However, some Mac users install it to be extra safe, or to kill viruses that they fear might be passed on via email or over networks to people using Windows.

In last week’s Mailbox, you advised someone that he could copy a 25-gigabyte file from a Mac to a Windows PC using an external hard disk formatted for the Windows FAT file system. But I believe that won’t work. Do you have another solution?

You are correct that I erred. I forgot that the FAT file system, the only Windows format to which Macs can save files, is limited to file sizes of up to 4 gigabytes. This is almost never a problem, except in the case of extraordinarily large files. I did offer several alternate solutions last week, including using a network or cable transfer. But here’s another: You can use a Mac-formatted external hard disk, or a Mac-formatted iPod acting as a hard disk, to transfer the file, provided you have installed on the Windows PC special software that allows Windows to read Mac-formatted disks. This software is called MacDrive, costs $50, and can be purchased at mediafour.com.

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.

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 security for smart phones, finding desktop computers with Microsoft Vista Ultimate preinstalled, and changing iTunes authorizations.

Having recently switched to a Windows-based smart phone (Treo 750) which has sensitive information on it, I am concerned about the need for antivirus and firewall security. Is security prudent for these phones?

First of all, the “Windows” on your phone isn’t in any way the same software as the “Windows” on your computer. Programs, including viruses and spyware, which are designed to run on a Windows PC typically won’t run on a Windows Mobile phone. There is some evidence of malicious software infecting phones, but the problem is quite minimal and I don’t see a need to install antivirus programs and firewalls on phones — yet.

I am limping along on Microsoft ME and would like to obtain Microsoft Vista “Ultimate.” I am finding that there are no desktop machines available in the stores that have “Ultimate” preinstalled on them. They all seem to have Vista Home Basic or Home Premium. Why is this?

Windows Vista Ultimate is the most expensive version, and doesn’t do very much more for an average consumer than Home Premium. But it can be found on some higher-end model computers in stores and can often be specified when ordering a higher-powered computer online from companies like Dell and Hewlett-Packard.

As you know, there is a limit of 5 PCs on which you can store/play your iTunes copy-protected music. I recently donated a PC but forgot to de-authorize it from my list of available computers. Is there a way to accomplish this even though I no longer have the machine?

Yes, Apple allows you to reset your authorizations, either by going to the account settings in iTunes or by contacting them and explaining the situation. The Account page in iTunes is reached by going to the iTunes store, and then selecting “Account” under Quick Links at the upper right. This reset will deauthorize all your machines, but that’s not as drastic as it sounds. It merely forces you to enter your password the next time you play a copy-protected song on any of the computers you want to remain authorized. After that, you’re all set.

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.

* * *

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 free antivirus software, different versions of the Palm Treo and emails that claim to be from financial institutions.

My computer is a virus-infected mess. I sometimes have to close over 20 pop-ups just to access the PC. Taking your advice, I tried to download the “free” AVG Anti-Virus, but there is nothing free about it. They ask for your credit-card info. What am I missing?

The company that makes AVG, Grisoft, offers both paid and free versions of the product. The free version must be downloaded from a separate Web site, free.grisoft.com. Most of the first few results in a Google search for “AVG” or “AVG anti-virus” point to this free version. Also, the free version is prominently featured at Download.com, the big site for downloading software that is owned by CNET.

Is there a significant difference between the Palm Treo 700p and the 700w phones — or is it just preference of software? Do they have the same ease of use?

A. The 700p uses the Palm operating system and the 700w uses the Windows Mobile operating system. The hardware is essentially the same, except for one big difference — the 700p’s screen has a significantly higher resolution than the 700w’s. There are also some different buttons on the keyboard.

But asking if two devices differ in “just preference of software” is like asking if living in a similar home in North Dakota or Florida differs “just” in terms of your preference in weather. The software is every bit as important as the hardware, and makes a huge difference in how the two Treos work.

I have reviewed both devices, and I find that the Windows Mobile software on the 700w is considerably inferior to the Palm operating system software on the 700p. Too many common actions in the Windows version take more steps than the same actions on the Palm OS version, and often require navigating menus. You are likely to use the stylus more often in the Windows version as well.

And, even though the software on the Windows version was made by Microsoft, it is actually worse at handling Microsoft Office and Adobe PDF email attachments than the built-in software for that purpose on the Palm OS version.

For my review of the 700p, see: ptech.wsj.com/archive/solution-20060607.html. For my review of the 700w, see: ptech.wsj.com/archive/ptech-20060105.html.

Last week, you advised readers never to trust any email from a financial institution because online criminals have gotten so good at faking such emails. Does that include emails from institutions where you have accounts, such as receipts for transactions at brokerages?

Yes and no. If you get an unexpected email from a bank, or brokerage, or payment service like PayPal, where you do have an account, I’d still advise ignoring it and never clicking on any link it contains. This is even true if the email suggests some problem with your account or advises that you need to log onto a web site to “verify” your account information. Such emails are very often just attempts to steal your passwords and account numbers. To double-check on such an email, phone the bank or brokerage, or manually call up its Web site.

However, if you have just bought or sold a stock, or performed an online banking action, and you get an email confirming the transaction, it could well be legitimate — provided it contains enough detail of a type criminals might find hard to replicate, and it arrives very quickly after the transaction was completed. I still wouldn’t click on any links in such an email, however. Remember, most financial institutions don’t have to ask you to supply account information they already have.

It’s really too bad that people have to look on such emails with such suspicion. Email could be a great tool for communications between banks and their customers. But, despite some strides, the technology and financial industries have so far failed to find a way to make email truly trustworthy and secure. And law-enforcement agencies have failed to stop the thefts of money and identities. So far, the crooks are winning in this arena. So you have to be extra careful.

* * *

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