A: Windows programs cannot be “converted” to run directly in the Mac operating system, which is called Snow Leopard. But, if you use virtualization software like Parallels or VMware fusion, and install Windows, then a Windows program like Microsoft Outlook can run simultaneously with your Mac programs. Technically, you are running it in Windows, but the two operating systems are active at the same time. With both of these virtualization products, you can even hide the entire Windows desktop, so that the Windows program you are running simply occupies a window on your Mac like any Mac program does. You don’t even notice that Windows is running.

In the case of files you created in Windows, the situation is even simpler. Most of the common types of files consumers use—including Microsoft Office documents, MP3 music files, MP4 video files, JPG picture files, text files, Adobe PDF files, and others—can be run in native Macintosh programs without conversion and without the need to run Windows programs. So you can just copy them to the Mac side and use them in Mac programs like iPhoto, iTunes, or the native Mac version of Microsoft Office, which uses the same file formats as the Windows version.

If you have an unusual or proprietary Windows file for which there isn’t an equivalent program on the Mac, you would run it in a Windows program, as described above.

If I am planning to upgrade a Windows XP machine to Windows 7, can I buy the upgrade copy of 7 or must I buy the full version?

A: According to Microsoft’s Web site, XP is one of the older versions of Windows upon which you can indeed indeed use the less expensive upgrade versions of Windows 7. The company’s online store says: “All editions of Windows XP and Windows Vista qualify you to upgrade. So, if you’re running either on your PC today, buy a package labeled ‘Upgrade’.”

I’ve been holding out (for what feels like forever) on purchasing a Netbook because I read that Apple was coming out with one. Can you tell me anything about when they might really begin selling them?

A: Apple executives have said repeatedly and emphatically that they don’t plan to offer a netbook, which is essentially a cheap, small laptop. Instead, Apple is widely believed to be working on a small slate or tablet device that would be controlled via a fingertip touch screen. This would be sort of like a larger iPhone or iPod Touch. The company hasn’t confirmed that such a product is in the works, but many analysts and Apple bloggers predict it will debut early next year.

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.

A friend’s Windows XP PC is having troubles. He wants to copy its contents onto a separate backup drive. Will he encounter problems if he tries to transfer this material to a Windows 7 unit he plans to buy when available?

He should have no problem at all with the data files, such as Office documents, music or photos. However, it may not be possible to transfer the programs and settings without reinstalling them from the original disks or downloaded installation files. And he may also have to re-install any patches or updates to these programs. Microsoft plans some sort of system to make this process simpler than it might be, but I don’t yet know how it will work.

I am not a super techie but would like to view Internet videos from my computer, attached to my TV. What do you recommend? Is there a system or a product that would be best for my needs?

You very likely don’t need any special product, other than the right cables and, if need be, adapters, to connect your computer and your TV. This choice depends on the details of your computer’s graphics capabilities and output ports, and the input ports and capabilities of your TV. All of this is much easier if the PC and TV are relatively modern — say, two years old or less. But, whatever their age, you should visit a competent electronics store that sells cables, provide the staff with the details of the two products, and seek their specific advice.

With the rising popularity of the netbook, do you know, or expect, that Apple will come out with a netbook? I would be very interested in getting one.

I know of no such plans. In fact, Apple officials have said they have no interest in producing a netbook, which is a small, inexpensive laptop, and have disparaged the category. However, Apple is quite secretive, and sometimes enters categories it had previously laughed off. Also, there are persistent rumors that Apple is working on a flat, tablet-style computer — perhaps a much larger version of its iPod Touch pocket-size device. If these rumors prove true, such a tablet might compete with netbooks.

Our daughter has asked for nothing but a Nintendo DS game system for more than a year now. Her birthday’s in two weeks. She says she’d be happy with the cheaper DS Lite, but is it worth going with the new DSi for $40 more? Do you think the DS Lite will become obsolete, in terms of new games for it?

Obviously, this depends on your budget, and I don’t think there’ll never be another new game for the DS Lite. But if the $40 price difference isn’t an obstacle, I’d go with the DSi, because I assume that, over time, more and more games and other software will emerge that will run only on the higher-end model.

• 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.

To my mind, this is more a parenting issue than a technology one. The easiest method would be to join Facebook yourself and become one of your teens’ ”friends” on each account they have. That might not sit well with your kids, but if you’re willing to be tough, you could make that a condition of their being on Facebook. You could also insist they use the network’s extensive privacy controls to guard their detailed information and activities from strangers.

There is a paid service called YouDiligence that claims it will notify you if certain words appear on a child’s Facebook page. But it requires that you be one of your child’s Facebook friends, so it is mainly a time-saver. Also, because it focuses on words, it doesn’t flag photos or other Facebook activity.

Another paid service, called imView, automatically takes pictures of the screen of the PC your child uses, at intervals you select, and allows you to view these screen shots at your leisure, from any Internet-connected PC. Its maker touts this as a way to monitor Facebook activity. I haven’t tested either of these two services.

I want to transfer my Mini DV taped videos from my video camera to my Mac. But my new MacBook has no Firewire port, which is the only port my camera includes — only USB ports. Am I stuck?

Maybe not. One option would be to see if you can borrow a Mac or Windows PC that does have a Firewire port, convert the videos to digital files on that borrowed machine, and then transfer the resulting files to your new Mac using an external hard disk or flash drive. Obviously, you wouldn’t want to have to do this often.

Another option: A company called Pixela (pixela-1.com) claims to have a Firewire-to-USB cable meant for exactly your situation. It is for Windows only, but might well work if you installed and ran Windows on your Mac. However, a glance at the company’s Web site shows it is out of the version of the cable that works with the North American, as opposed to European, video standard. If you are in North America, you might check with the company to see if and when the correct version will be available. One important caution: I haven’t tested it, so don’t know how well it works.

My computer crashed last fall, and I lost thousands of iTunes songs. I would like to copy all the songs to my new computer from my iPod, which still contains them. However, iTunes allows only purchased songs to be returned. Is there software that would help me?

Yes. There are several utility programs designed to copy the contents of an iPod back to a Windows or Mac computer. The one I usually recommend, because I have found it works well, is called Music Rescue. It costs 10 British pounds, or about $15 at current exchange rates. It can be purchased at kennettnet.co.uk.

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.

Should I install Microsoft’s “SP3″ upgrade to Windows XP? I hear opinions on both sides.

In general, I recommend this upgrade, officially called Service Pack 3, because it beefs up security, and that helps not only you, but all Windows users, to avoid the spread of malicious software. If your PC is more secure, it is less likely to be used as a source from which other PCs can be infected.

I have upgraded a couple of XP PCs to SP3 without any downside. However, like you, I have also heard from some users that the upgrade caused them problems.

As with any major operating-system upgrade, either outcome can occur, depending upon your computer’s particular configuration and condition. So, if you’re on the fence, consider your level of concern about security.

How do cellular data cards compare with fast cable modems in terms of Internet speed? Are these cards more secure than Wi-Fi?

In my experience, using and testing cellular data cards on various laptops, they typically deliver, in real day-to-day use, somewhere between 300 kilobits per second and 1.5 megabits per second. By contrast, a fast cable Internet service can actually deliver up to 16 mbps. So cable is much faster.

Your security question is much more complicated. Wi-Fi security can range from very poor to quite good. It depends on where and how you use Wi-Fi, how you or others have set up the wireless network, and how you have configured your own computer.

Accessing the Internet over a cellular network is a more controlled process, because the cellphone-network operator manages the transmission, and in most cases supplies and configures the software on your computer. So, it is likely to be safer than the worst Wi-Fi setups. But I would never suggest that cellular data card transmissions are invulnerable to hackers or criminals.

What’s the difference between file-based backup and image-based backup software? Why would I choose one over the other?

Image-based backup software copies an image of your entire hard-disk, including all the programs, settings and obscure files that you never see. While it can be used to recover individual files, in some cases, it is mainly designed to allow you to restore your entire hard disk in the event that you lose it all.

File-based backup software, which is more common among consumers, is typically designed to preserve a copy of only your personal data, the material you can’t re-purchase or re-install if your hard disk dies.

That includes word-processing files, spreadsheets, presentations, emails, contacts, calendar items, photos and other items you created. It also is often used to back up music and video files that would be time-consuming, or very expensive, to re-acquire. And in some cases, it can preserve settings and preferences, such as Web bookmarks.

Both types of backup generally begin with a time-consuming initial session, followed by shorter sessions to update the backup with incremental changes.

Many people choose file-based backup because it occupies less space, and is generally quicker and also less expensive. Image-based backup is for folks who are willing to spend the added money and time to be sure they can restore their whole computer, or clone its contents completely to another machine.

• 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.

I am in the market for a new HDTV and the newspaper ads are using terminology that I’m unfamiliar with. Do TVs rated at “720p” provide the same quality picture as those rated at “1080p”?

Technically, the answer is no, but it may not matter. The 1080p resolution is certainly higher, but almost nobody can tell the difference between the same material shown in the two resolutions on TV screens up to around 50″ in size and at the typical distances from which people watch those screens. Not only that, but most sources of video content, with the exception of Blu-ray discs, can’t even fully utilize 1080p. Major TV networks don’t use it yet because it requires a lot of bandwidth.

If you can afford a set that can handle 1080p, you might want to buy it so that you are ready in case a lot of 1080p content one day becomes available. You might also want a 1080p set if you are a videophile; have an enormous screen or a projector that fills a large wall; or if you play a lot of Blu-ray discs and believe you can discern the difference on a typical-sized screen. Otherwise, you could save money by buying a 720p set and you might never know the difference.

In 2006, you recommended a powerline adapter for Internet access by Netgear, the XE104. Is this still a good buy or are there others by now that are better?

I haven’t tested powerline adapters, the gadgets that route computer networks over standard home electrical wiring, since that date. Netgear and its competitors — such as Linksys and Belkin — have, naturally, come out with newer, faster units since then. But I am still personally using the XE104 successfully and feel I continue to get my money’s worth from it. It is still being sold. The newer units typically have greater speed in order to do a better job of streaming video around a home, but they work in basically the same way.

I have a Windows XP system, and things work well with my cable modem in my office. But when I’m on the road using Wi-Fi, I can receive emails, but can’t reply or send out. Any idea on how to resolve this problem?

This usually happens because the Wi-Fi provider is blocking the outgoing email server (called an “SMTP” server) that you or your IT department has set up in your email program. Some providers block all such outgoing servers. There are a number of possible solutions. The simplest is to use a Web-based email service, like Gmail or Yahoo Mail, or the Web-based version of your usual service. If your email is provided by your company, you may be able to access a version of Microsoft Outlook over the Internet that will work.

Another possibility is to ask the provider at the hotel or airport what SMTP server it does allow — usually its own — and enter it into your email program’s settings, if you know how. Yet another option would be to use a data card from a cellphone carrier, which I have found can usually overcome this problem. There may be other workarounds, and I invite readers to suggest them.

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

I need some help sending videos to others. It seems that every video I try to send in various ways is always too large. I’ve tried to use a program that works with Outlook to compress the email attachment, but it’s always still too large. Is there a solution other than uploading them onto YouTube or something similar?

I suggest you try one of the services that specifically exist to transmit files that are too large for email. They typically work by having you upload the files to their servers, which, unlike YouTube, don’t expose them to the world. Seconds after you upload these files, your recipients receive an email that includes a specific link to the file you uploaded. The email is small because it includes only the link, not the file itself. The recipient clicks on the link, and the file is downloaded to his or her computer.

The service I use for this is called YouSendIt, and can be accessed at yousendit.com. It works in all the major Web browsers, and on both Windows and Macintosh computers. The company has a free plan that covers files of up to 100 megabytes in size, and allows each file to be downloaded up to 100 times, or up to a gigabyte of total downloads each month. For $10 a month, you get a maximum file size of two gigabytes, 500 downloads per file, and a monthly maximum limit of 40 gigabytes.

In my experience, YouSendIt works well. It can be used directly from within a browser, or via a small program called YouSendIt Express, that lives on your computer and handles large files faster than the browser version does. YouSendIt also offers an Outlook plug-in that can automatically route large downloads via the service rather than through regular email, though I haven’t tested this plug-in.

Our daughter is heading off to college this fall. She will be an art/graphic-design major, and the school recommended that she buy an Apple MacBook. I’m not sure if she should get what the college calls the “midlevel MacBook” or the “advanced MacBook.” The only differences are a slightly faster processor, a hard disk that is 40 gigabytes larger, and a “SuperDrive” for CDs and DVDs rather than a “Combo” drive. The price difference is $90. Which should we buy?

Either machine would be fine, and a lot depends on your budget, since college itself is of course very expensive. But I think, in this case, the extra $90 would be worth paying. This has nothing to do with the processor speed, which she probably wouldn’t even notice. But, if she is going to be creating a lot of graphics files, which can be large, the extra hard-disk space could be important.

The same goes for the CD/DVD drive options. The “SuperDrive” is Apple’s term for a drive that can create both DVDs and CDs, while the “Combo” drive can create only CDs. (Both drives can play both types of disks.) For someone who is producing large files, the ability to create DVDs can be handy, since DVDs have much higher capacities than CDs.

My laptop has been infected by rogue viruses, posing as antispyware programs, that I can’t get rid of. When I go on Google, I find a number of sites that claim to offer free software that will get rid of them, but I am reluctant to download anything onto my machine from a source that I am not sure of. What’s a reliable program that will do that job?

I would immediately buy a genuine, legitimate commercial antispyware program, install it and run it. The best ones I know of are Spyware Doctor by PC Tools, at pctools.com, and Spy Sweeper from Webroot, at Webroot.com. Each costs $30, but that price can save you a lot of heartache.

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

Has anyone come up with a method that allows people to take pictures with a regular digital camera and then download them wirelessly to a computer, and/or perhaps to the Internet?

There have been a few digital cameras with built-in Wi-Fi wireless capability, but the best and simplest method I know is a $100 product called Eye-Fi. This tiny gadget looks and works like a regular, garden-variety SD memory card, but it packs a Wi-Fi transmitter inside. It fits into a standard SD memory-card slot and is compatible with a wide range of camera models from Canon (CAJ), Kodak (EK), Nikon (NINOF.PK) and others.

Coupled with clever software, and a clever Web site, the Eye-Fi card automatically zips your pictures wirelessly to your PC or Mac, and/or to your choice of over 20 online photo-sharing services.

For more information, see www.eye.fi. For a list of compatible cameras, see support.eye.fi/compatibility/. For a full review of the product, see: solution.allthingsd.com/20071121/.

You mentioned last week that SugarSync might be a good solution for backups, so if one computer dies your files still exist on another system. But what if the doomed computer doesn’t actually die but its files are corrupted by malicious software? Do those newly corrupted files overwrite the good copies on your SugarSync network?

They could do so, depending on which folders you had chosen to replicate on your other computers. Automatic-synchronization services like SugarSync have a tough time telling whether changes to a file are deliberate, accidental or the result of some sort of corruption. Though the last is rare, it could look to SugarSync like you had changed the file on purpose.

One way to guard against that is for a service to offer “versioning” — the practice of maintaining multiple past copies of a file. That way, if a change isn’t intentional, you can go back to the prior, pristine version. Sharpcast, the company that makes SugarSync, says it is planning to add versioning to the service, but offers no specific date. In the meantime, one way to back up a file without fear of its being overwritten by a corrupted version is to upload it to SugarSync’s special “Web Archive” folder, whose contents are never automatically updated.

Have you ever reviewed and suggested a media player for connecting to a home theater to play all songs, videos and photos that exist on your home computers?

Yes, I have reviewed several over the years. The one I find simplest and best designed is Apple TV, which, despite its name, can work fine in a household with no other Apple (AAPL) hardware. It costs $229 and is a small, thin, unobtrusive box that fetches music, photos and videos from your home network using either a wired or a wireless connection. It can connect to your TV set or home theater via a variety of analog and digital ports, including component-video, HDMI, and optical and analog audio. It supports high-definition video and works with any computer, Windows or Mac, that has Apple’s free iTunes software installed and running.

Apple TV handles many standard photo, music and video formats, but it is limited to music and video files that iTunes can handle. That excludes copy-protected files in Microsoft’s formats, and certain open Microsoft formats, but includes common files like MP3s. Apple TV also allows you to access YouTube and to purchase music and TV shows from Apple, and rent movies from Apple, without the use of a computer.

• 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.

My IT department will not turn on the feature in our servers that would allow me to receive corporate email on my iPhone. This has forced me to revert back to my BlackBerry Pearl. Can I transfer my iTunes music to my Pearl?

It depends on what you mean by “iTunes music.” If you mean music you bought from the iTunes store in protected format — which describes most of the store’s catalog — the Pearl can’t play it, unless you go through a laborious multistep process to convert it to unprotected files. If you mean unprotected music that is managed by the iTunes program on your PC, the Pearl can handle it as long as it is in open formats supported by the Pearl, including the MP3 or open AAC formats.

To get these files into your Pearl, simply use the music-transfer software that came with the Pearl to copy the songs from your computer’s hard disk to either the Pearl’s internal memory or to a flash memory card you may have in your Pearl.

I recently purchased a new iMac with the Leopard operating system, and have installed Windows Vista on it as well, using Leopard’s Boot Camp feature, so the Mac can boot into either OS. I would like both of those operating systems to share an external hard drive so I can back up my files. Is it possible to do that?

Yes, provided you follow one of two scenarios. The first would be to format the external drive as a Windows drive, but be careful to use the Windows format called “FAT32,” not the one called NTFS. Out of the box, Macs can see all Windows drives and can read from them all. But they can only save files to Windows drives that use the FAT32 system for organizing files. The downside of this is that the FAT32 system only allows files of up to 4 gigabytes each.

The other scenario would be to use a Mac-formatted external drive, which doesn’t have that limitation. Of course the Mac operating system can handle such drives perfectly, but Windows can’t even see them. However, in your Vista setup, you can install a third-party Windows program called MacDrive 7, which allows Windows to both read from, and write to, Mac-formatted drives. I have tested it successfully with Vista under Boot Camp on an iMac. The $50 program can be downloaded from mediafour.com.

The hard disk on my new Sony VAIO laptop is filling up fast. It is trying to get me to watch a lot of movie trailers. Is all that video stored in my machine somewhere and if so can I dump some of it out?

If your Sony laptop is like mine, not only are the unwanted movie trailers pre-loaded on your hard disk, but so are the entire movies, which Sony actually charges you to watch. In my case, these files took up over 4 gigabytes of precious disk space. This is a particularly outrageous example of what I call “craplets,” unwanted trial software that litters new Windows desktops. You can delete these files and reclaim all that disk space without any harm to your computer.

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

I am shopping for a new laptop, and noticed that some of the models in which I am interested come with Windows Vista Business edition instead of Home Premium, which I understand is the main consumer version. What would I be missing if I went with the Business version instead?

The main thing Vista Business lacks that Home Premium includes is a series of multimedia features. These include Media Center, which allows you to play songs and videos, and view photos, from across a room. In addition, Home Premium offers Windows Movie Maker software for creating movies, DVD maker, and several games the Business version lacks.

On the other hand, the Business edition has some things Home Premium doesn’t, including built-in programs for doing a complete PC backup, for faxing and scanning, and for remotely running programs on another computer. For the most part, however, Vista Business looks and works like Home Premium.

I just bought a new laptop, and want to transfer to it the Firefox bookmarks I have on my old desktop. How can I do that?

There are a number of possible methods, but here’s a simple, straightforward approach.

First, you export the bookmarks from Firefox on your old desktop PC, which creates a single file containing the bookmarks. Then, you copy that file, which Firefox names by default “bookmarks.html,” to a CD or portable USB drive or some other medium you can use to transfer files between computers. Then, you copy the file to the new laptop. Finally, you import the file into the fresh copy of Firefox on the new laptop.

To carry out this process, you use Firefox’s import and export function for bookmarks. On the first computer, from the Firefox Bookmarks menu, choose “Organize bookmarks.” Then, once the bookmark window opens, go to the File menu and choose “Export.” That will create the bookmarks file. After the file is on the second computer, launch Firefox and repeat the process, only this time choose “Import,” and then click on “From File,” and select the file you brought over.

I have Word 2003 and have just started to receive Word 2007 documents, which I cannot open. What is the best solution?

Word 2007 has a new default file format, called DOCX, that is incompatible with older versions, which rely on the long-standing DOC format. The new version can be set to always save files in the old format, but not everyone knows that or chooses to do so.

However, folks such as you with the 2003 version of Word can install a free “Compatibility Pack” from Microsoft that will allow your copy of Word to read the new format. It can be obtained from the company’s Download Center, at www.microsoft.com/downloads. You’ll find it listed there under “Popular Downloads.”

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

With the new iPods coming out, how do you deactivate an old one? I think Apple only allows a certain number to be used with an account.

You don’t have to deactivate an iPod if you replace it. The copy-protection rules imposed on Apple by the entertainment companies allow for copy-protected music and videos purchased from the iTunes Music Store to be stored and played on an unlimited number of iPods.

The only “deactivation” iTunes users have to perform is on a computer — Windows or Mac — because the copy-protection rules allow purchased, copy-protected songs and videos to be played on no more than five computers at a time. So, before you replace a computer on which you are storing such purchased, protected iTunes material, you should deauthorize the machine by going to the “Store” menu in iTunes and selecting “Deauthorize Computer…”.

Of course, if you aren’t at or near the five-computer limit, this issue may not matter. It’s also irrelevant if none of the music or videos you play from within iTunes is copy-protected material purchased from the iTunes store. You can happily use iTunes and iPods without buying any copy-protected stuff from Apple. You can restrict your music and videos to those you copy from legally obtained CDs, those you create yourself, or those you buy in unprotected formats from iTunes, or other sites, like eMusic.

I have a printer hard-wired to a desktop computer, but would like it to be available to my laptop wirelessly over my home network. How can I do this?

There are two main methods, assuming the printer doesn’t have a built-in networking port or Wi-Fi transmitter. One method is to buy a small box called a print server and plug it into your router. Then, you plug the printer into the print server, and, with the right software and settings, it will appear on your network and be available to any computer on the network, wired or wireless.

The same companies that make routers, such as Linksys and Belkin, also often make these print servers. The other method is to buy a wireless router that has such a print-server function built-in, with a USB port for connecting a printer.

If I have a laptop with Wi-Fi capability, does that mean I can surf the Web while sitting in a car?

Yes, but only if the car is in range of a Wi-Fi network that is either open (not password-protected) or for which you know the password. And it would only be practical if the car was stopped or parked, since a car moving at normal speed would very quickly drive out of range of any networks you encountered.

A better option, which works even when a car is moving, is to purchase a high-speed cellular wireless modem for your laptop, or buy a laptop with such a modem built-in. These modems, which get you on the Internet via citywide cellular-data networks instead of Wi-Fi, can remain in range for miles. But they require hefty fees, typically $60 a month. And, of course, you should only be surfing the net in a moving car if you are a passenger in that car, not the driver.

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