I have Firefox on my home laptop, but Internet Explorer on my office laptop. Can I transfer my Firefox bookmarks on my home computer to IE on my office computer using the Foxmarks bookmark-synchronization service you recommended? And how would I go about doing it?

Yes. You start by uploading your bookmarks from Firefox at home to your Foxmarks Web account, using the Firefox version of Foxmarks. That will establish the bookmark collection on the Web site as identical to your Firefox collection. Then, you install the IE version of Foxmarks on your office computer, and, when it prompts you to sync, you can either merge the Web-based bookmarks you previously uploaded from Firefox with the ones already on IE, or choose the option to overwrite the IE bookmarks entirely with the ones online.

Does the Foxmarks service work with AOL’s browser bookmarks?

AOL’s browser is not supported. Neither are some other browsers, such as Opera or Google’s Chrome. Foxmarks currently comes in versions only for Internet Explorer, Firefox and Safari (Mac version only). The Firefox version also works with Flock, which is a browser heavily based on Firefox.

Do you have any idea what the realistic hardware requirements will be to run Windows 7?

Microsoft hasn’t announced these yet. But the requirements for the current beta version are likely to be similar to those for the final release. The beta hardware requirements are: a 1 GHz 32-bit or 64-bit processor; 1 GB of system memory; 16 GB of available disk space; support for DirectX 9 graphics with 128 MB memory available for graphics; and a DVD-R/W Drive.

In the past, Microsoft’s minimum requirements have tended to understate what’s needed to run Windows well, even when doing typical tasks. It’s too early to say if this will be true of Windows 7. But I can say that, in my testing so far, the beta of Windows 7 runs much more quickly and smoothly than Vista on the same hardware.

• 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.

Do Macs last longer than Windows PCs? I am willing to pay the additional cost for a Mac if it will last significantly longer, but if it has approximately the same lifespan as a PC from a reputable manufacturer, I will stay with PCs.

In my years of using both types of computers daily, I have never noticed a significant difference in when Macs and Windows PCs become unfit to use, and I have never seen claims from Apple (AAPL) that its computers last longer than competing models. Obviously, on the Windows side, there’s a much greater variety of manufacturers and of quality levels, while Apple makes all Macs, and receives generally high marks in well-known surveys of reliability. But so do some Windows PC makers. All computer makers turn out the occasional lemon, and how long a computer “lasts” depends tremendously on how you use it and how you judge its usefulness over time.

My laptop hard drive crashed last year and I lost some digital pictures that were on it. My daughter had accidentally copied those digital pictures onto her iPod but she didn’t select the option to store them at full resolution. I know I can get the pictures back off the iPod, but is there any software that can get them back at full resolution?

Not as far as I know. Unless you tell iTunes to store the photo at full resolution, what is on the iPod is a version of the photo that has been scaled down for the iPod’s screen resolution and storage capacity, and that is the resolution they would retain if you copied them back to a computer.

I have an H-P (HPQ) laptop using Windows XP and Microsoft (MSFT) Office 2003. If I purchase a new H-P laptop with Vista and Office 2007, what must be done to make the two machines compatible? My goal is to be able to take a copy of Office files from one computer and use them on the other.

The difference in the operating systems won’t affect your plan, but the difference in the Office versions might. The newer 2007 version of Office can easily handle your files from the older version. But Office 2003 can’t handle files in the new default Office formats introduced in the 2007 version. These formats use file suffixes that end in the letter x. For instance, the new Word format has an extension of docx, instead of the old, familiar doc.

Luckily, the new Office can still save files automatically in the old formats, if you change a setting. Here’s how.

On the computer with the new version of Office, click on the round “Office Button” at the top left of the 2007 versions of Word, Excel and PowerPoint. Then, in the window that appears, click on “Options.” In the next screen that comes up, click on “Save” in the column at the left. In the panel that appears at the right, you’ll notice an option called “Save Files in this format,” with a drop-down list of choices next to it. Display the list of choices by clicking on the arrow and select the format that corresponds to Office 2003. Then, click OK at the bottom of the window. For instance, in Word 2007, the format you want is called “Word 97-2003 Document (*.doc).”

The other option is to enable Office 2003 to handle the new formats, by downloading a free “Compatibility Pack” 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 for free at the new All Things Digital web site, http://walt.allthingsd.com.

I want to buy a new ultralight laptop for travel. Few are available with Windows XP, which I would prefer. If I get a Vista machine, will I have compatibility issues with transferring files back and forth between it and my older laptops, both of which have XP operating systems and MS Office 2003?

Your Microsoft (MSFT) Office files, and other standard files, such as photos, songs and PDF documents, should all be compatible with both Vista and XP. While Vista has compatibility problems with some programs and some hardware, in my tests I have never found that Vista caused compatibility problems with standard, common types of files.

I plan to install Windows XP on my Apple (AAPL) iMac using Boot Camp. Whenever I am using the Windows side of the machine, I plan to shut off access to the Internet — no Web browsing or email. I even intend to unplug my wireless base station. Will this protect me from getting the Windows viruses?

Well, that’s a drastic plan, but it will probably work, since most viruses and other malicious software are acquired via email or Web sites. However, by cutting yourself off from the Internet, you may make your computer less useful while running Windows. Many programs have Internet components, and those that run locally often download new versions and features over the Internet. Plus, Microsoft distributes updates for Windows and Office using the Internet, including security fixes. For those reasons, it might be more effective to install security software on the Windows portion of your Mac and leave the Internet connection on.

I have a relatively new PC with Windows Vista. Typically, I may have five or six programs running at the same time, sometimes with multiple documents open in each one, and I like to leave my PC this way. However, I’ve noticed that every few weeks or so, Vista has an annoying tendency to restart my PC when I’m away from it, and I see a message that “Your computer was restarted to finish installing updates.” Is there any way to prevent or minimize this?

Yes. In the settings for Microsoft’s automatic update service, called Windows Update, the recommended option is to automatically download updates and install them. The second step, installing the updates, can lead to a restart. But you can change the settings to minimize or eliminate the annoyance this causes.

You can choose a specific schedule for installing the updates at a time when you won’t be interrupted. Or, you can choose an option called “Download updates but let me choose whether to install them.” A third option is called “Check for updates but let me choose whether to download and install them.” You could opt out of the update program, but that could leave your PC vulnerable to malicious software.

These options can be found by opening the Windows Security Center, then clicking on “Windows Update” at the upper left. Then, in the next window, click on “Change settings” in the left column. Similar settings are also available in Windows XP, by opening the Security Center and clicking on “Manage Security Settings for: Automatic Updates.”

• 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.

When will Google offer its much-discussed cellphone for sale?

Google says it isn’t planning to build or sell mobile phones. Instead, it is developing a cellphone operating system, or software platform, called Android. And it has assembled an alliance of companies, including phone makers and cellular network providers, to create phones based on this new platform. This group is called the Open Handset Alliance. In addition, since Android will be so-called “open source” software, Google expects numerous developers around the world, large and small, to modify the operating system and create programs that will run on it.

If all goes according to plan, Google says it expects to see many different Android-based cellphones and other mobile devices, from a variety of manufacturers and carriers, in various designs and with differing functionality and capabilities. Some may be larger-screen “smart phones,” similar to an iPhone or BlackBerry. Others might be smaller, simpler phones. Still others might fall somewhere between an iPhone and a small laptop.

Google officials say they expect the first Android devices to be available later this year.

After reading your Jan. 3 column, I looked unsuccessfully for a Home and Student version of Office for Mac 2004. Does such a version exist?

In the 2004 release of Microsoft Office for the Mac, this low-priced version had a different name: the Student and Teacher edition. Microsoft presumably changed the name of this $150 product to the Home and Student edition in both Office 2007 for Windows and Office 2008 for the Mac, because, while it was technically limited for sale to families containing students or teachers, no proof was required and it was widely purchased by consumers in general.

However, there’s a big difference between the latest Windows and Mac versions of the Home and Student edition. In the Mac version, it includes Word, Excel, PowerPoint and Entourage, Microsoft’s equivalent of Outlook on the Mac, which, like Outlook, includes email, calendar and contact functions. But the new Windows version now omits Outlook, and instead substitutes OneNote, a note-taking and information organizing program that is far less commonly used. So, Windows users must spend much more money to get a version of Office that includes Word, Excel, PowerPoint and Outlook.

Is there a way to back up Microsoft Outlook Express emails, particularly Inbox items?

Outlook Express stores your emails in database files, with all the messages in each of your mail folders lumped into a single such file. These files can be backed up, or copied, onto other hard disks, or storage media.

The email data files are usually buried in obscure subfolders in Windows. But you can locate them by clicking on the Tools menu, then Options. This will open a tabbed window. In this window, click on the tab called Maintenance, then the button called Store Folder. This will generally give you a long, complicated path to the folder.

Next, copy this path by selecting it and pressing Control and C. Then, click on the Start menu, select “Run…”, and then press Control and V and then click OK. This should open the folder that contains your email. The inbox is contained in a file called Inbox.dbx. This is the file you will want to back up. If you want to back up other folders, such as the Sent mail folder, you will find them along with the inbox file, with the same “.dbx” suffix.

Some backup programs may automate this process by simply allowing you to designate that you want to back up your Outlook Express emails. There are even some programs specially designed to back up Outlook Express messages. You can find some of these by simply performing a Web search on “backup Outlook Express.”

• 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.

I couldn’t find any columns on products you recommend for monitoring kids’ Web access and installing parental controls. I recently purchased a new computer for my 9-year-old daughter. I want to make sure she can only access specific Web sites and I want to protect her from inappropriate spam and chatting.

If you have a computer running one of the newer versions of Windows or the Macintosh operating system, I recommend using the extensive parental controls that are now built right into those operating systems. While you can never underestimate the ingenuity of computer-savvy kids, these built-in controls, if properly used, are generally harder to evade than the ones provided by third-party software.

I did recently review these built-in parental controls, which appear in Windows Vista, and in the Tiger and Leopard editions of the Mac’s OS X operating system. You can find that column at: ptech.allthingsd.com/20070614.

I want to switch to a Mac, but my life is on Microsoft Outlook, which is only available on Windows. Is there a simple way to convert all of this data to programs on the Mac?

There is a $10 program that performs this task. It’s called O2M (Outlook to Mac) and is from a company called Little Machines. It can be downloaded at littlemachines.com, where you also will find details about the Mac programs with which it works. This is a Windows program, which transfers your Outlook data into files you copy to your Mac. You then manually import these files into your Mac programs.

According to the company, the program exports Outlook email, email attachments, contacts and calendar appointments and allows you to import this data into Apple’s built-in email, address book and calendar programs, as well as into Microsoft Entourage, and other third-party programs.

Another approach is to install Windows on your Mac, and keep running Outlook. If you do this using the Parallels or Fusion virtualization programs ($80 each, plus the cost of Windows,) you can run Outlook simultaneously with your Mac programs.

Does the new version of Microsoft Office for the Mac work on pre-Intel Mac models?

Microsoft says it does, though I didn’t test it on one of these older machines. According to Microsoft, the new Office 2008 runs on any Mac “with an Intel, PowerPC G5, or PowerPC G4 (500 MHz or faster) processor.” However, you also need a relatively recent version of the Mac operating system, either the new Leopard edition, or the latest update (called 10.4.9) of the Tiger edition.

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.

Apple makes beautiful hardware, and, in my experience, it runs Windows quite well. In fact, the mouse and keyboard problems you cite are easily overcome, since you can plug almost any USB keyboard and mouse made for Windows into a Mac and they will work fine, right-mouse button and all.

However, what makes a Mac a Mac is primarily Apple’s OS X operating system, and the software Apple bundles with it, the iLife suite. If you don’t intend to use that, I don’t see much point in buying an Apple computer. You won’t get the advantage of the Mac’s lack of viruses and spyware, which stem from the operating system, not the hardware. And you can buy a Windows computer for less than the least expensive Mac.

In my view, the main value of the Mac’s ability to run Windows is that it allows Apple owners to use the few Windows programs they require or prefer that lack Mac equivalents, while primarily running the Mac operating system and programs designed for it.

How can one send an email to a group of people without all of their individual email addresses showing?

The most common method is to put your own email address in the “To” field and the names of all the recipients in the “Bcc” field, which is designed to be invisible. There’s always a danger someone quickly scanning just headers will decide not to read the email, since it isn’t addressed to her, but most email veterans understand the technique.

Is there a way to regain the traditional drop-down menus and other interface items in the new, redesigned Microsoft Office 2007?

There is at least one third-party add-in program designed to do this, but I haven’t tested it. It’s called Classic Menu for Office 2007, and can be found at www.addintools.com.

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

On two different new computers, I’ve created Word files and they’re automatically saved with the extension “.docx.” What is that? When I send these files via email, no one can open them. Can you shed some light?

In the 2007 version of Microsoft Office for Windows, which you appear to have on your two new PCs, Microsoft introduced new default file formats whose extensions end in the letter “x”. The one for Word is “docx,” for Excel it’s “xlsx” and for PowerPoint it’s “pptx.” You are using Word 2007, and all of your files are thus automatically being saved in the “docx” format.

Your correspondents can’t open these files because they are using older versions of Office that don’t recognize the new formats. Microsoft has made available a free auto-conversion patch for the older Windows Office versions, but most people don’t have this patch. (It can be found at microsoft.com/downloads under “Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats.”)

There’s also a kludgy free stand-alone converter from Microsoft for the Mac versions of Word and PowerPoint, available at microsoft.com/mac under the name “Microsoft Office Open XML File Format Converter for Mac.”

Unless you can persuade all of your correspondents to install these workarounds, I suggest you change a setting in Word 2007 so that, henceforth, all of your files will be saved in the traditional “doc” format. That familiar format isn’t only compatible with older versions of Microsoft Office, but with many other programs, on both Windows and the Macintosh.

To make the change, first click on the round “Office Button” at the top left of Word 2007. Then, at the lower right of the window that appears, click on “Word Options.” In the next screen that comes up, click on “Save” in the column at the left. In the panel that appears at the right, you’ll notice an option called “Save Files in this format,” with a drop-down list of choices next to it. Display the list of choices by clicking on the arrow and select “Word 97-2003 Document (*.doc)”. Then, click OK at the bottom of the window.

Microsoft warns that some new features in Word 2007 won’t translate into the old format, but I believe that this will prove irrelevant in 99% of cases and is outweighed in any case by the incompatibility you have run into.

How can I transfer all my Outlook contacts from a Windows PC to a Macintosh contacts program?

There are a number of methods. You can use a PDA or smart phone that can synchronize the contacts with a Mac, after having first synchronized with Outlook on your PC. Or you can use a $10 program called O2M, which is specifically designed to move Outlook data to a variety of Mac programs. It can be downloaded at littlemachines.com.

Or you could get Apple to do it. The company offers a basic file transfer for free if you buy the Mac from an Apple retail store. But, if you want Apple to move Outlook contacts in just the way you want, you may have to purchase the company’s $99 a year ProCare service, which comes with a more complete transfer service.

I recently replaced an old Windows XP computer that was running very slowly. I want to continue to use it as the computer for our young kids, and I was thinking that if I format the hard drive and reinstall XP (which I bought to upgrade the machine a while back), it will probably improve its performance. Do you agree? And, can I reinstall my copy of XP, when I have already “activated” the software when I originally installed it?

I do agree that the computer will likely run faster after you wipe the hard drive and reinstall Windows. That is the usual outcome. And it should be possible to use it legally, as long as you haven’t made any major changes to the hardware, since Microsoft’s activation system typically allows Windows to be reinstalled on the same machine. If activation fails, you can call Microsoft and explain that it’s the same machine, and the company says it will usually OK activation in such cases.

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 using an iPhone overseas for data purposes, running Microsoft Office 2000 on Vista and using broadband-provider email in two locations.

You recently wrote that iPhone owners using the device overseas must roam on AT&T at high rates, because the iPhone won’t work with SIM cards from foreign carriers. You noted that AT&T has a monthly plan that cuts these per-call voice rates somewhat. But what are the options for using an iPhone overseas for data purposes, such as email and Internet browsing?

Until Apple initiates iPhone service with foreign carriers, which is expected to be a gradual process that will begin in Europe, iPhone owners traveling abroad will be forced to roam on AT&T and to pay through the nose for data as well as voice calls made over cellular-phone networks. They won’t be able to buy cheaper service from a local foreign carrier and enable it by simply replacing the phone’s AT&T SIM card with the local carrier’s.

In addition, it is important to note that, even if you are willing to swallow these huge voice-and-data rates, you must call AT&T (formerly Cingular) before you leave the U.S. with your iPhone (or any AT&T phone) to modify, or “provision,” your calling plan so it will even work overseas.

Here are the details. Note that these prices and plans apply to many other phones AT&T sells, not just the iPhone.

To recap the voice-calling situation, AT&T charges very high fees, which can be mitigated a bit by adding a special $5.99 monthly add-on feature, called AT&T World Traveler, to their plans. This voice feature allows you to roam in 190 countries and gives you discounts on calls from 80 countries. For instance, in France, Italy, Germany, and Britain, you pay a still-high 99 cents a minute, compared with an even worse $1.29 without the plan. In Hong Kong or Israel, you pay a whopping $1.99 a minute, instead of an even more outrageous $2.29 or $2.49, respectively, a minute.

For email and the Web, the best bet for iPhone owners is to avoid using cellular networks and employ the phone’s Wi-Fi capability, which can cost nothing extra. Try to find a free or reasonably priced Wi-Fi hot spot in which to check email and do Web browsing. You may even be able to make cheap voice calls this way using Internet-based calling services like JaJah (mobile.jajah.com) which, in my domestic tests, worked properly via the iPhone’s Web browser.

However, if you need to check email constantly or frequently, you are unlikely to be able to depend solely on the Wi-Fi method. You can rely on AT&T roaming to do this over foreign cellular services, but, as with the voice call situation, it will cost a fortune.

AT&T offers an add-on plan for $24.99 a month, called the “PDA/Smartphone/iPhone International Data Plan.” This is on top of the $5.99-a-month voice plan, and is also additive to the $20 a month for unlimited data when in the U.S. that is built into your base plan. But it isn’t unlimited. You get only 20 megabytes of overseas data use a month, and pay a stiff $.005 a kilobyte for all data use above that.

Plus, this international-data plan only works in 29 countries. Outside those countries, the cost is an astounding $.0195 a kilobyte, or roughly $20 a megabyte. To put that in perspective, a single email with a medium-resolution picture attached could amount to a megabyte. More information is at www.att.com/wirelessinternational.

One more note: apparently AT&T can and will cancel your roaming service overseas if it notices what it considers an unusually high number of calls being made. One reader with an iPhone reported that, after arranging belatedly in Europe to get the voice-roaming service, he was suddenly cut off when he reached India, with AT&T explaining the cutoff as an attempt to prevent suspected fraud.

According to this reader, AT&T said he had been cut off “because there were ‘too many calls from India and other countries’ and they did not think it was possible anyone could be doing that for real, so to protect me, they cancelled the service.” An AT&T spokesman says the company can’t comment on the details of this particular case without knowing the traveler’s phone number.

You say Office 2003 runs OK on Windows Vista. I have been using Office 2000 and it does everything I need. Will it also run OK on Vista?

Microsoft doesn’t officially support Office 2000 on Vista. It may work, but I haven’t tested it.

Is there a way that I can use my same email address both at my home in New Jersey and at my winter place in Florida, even though I have broadband Internet service in New Jersey but am limited to dial-up Internet access from a different provider in Florida?

Some broadband providers also make available a supplementary dial-up service for their customers, which may be free or cost extra. Check with your broadband service to see if it offers this option.

If not, you could simply use an email account that isn’t necessarily tied to an access provider at all, such as Web-based email services from Yahoo, Google or Microsoft. You could switch to one of these permanently, and use it in both locations, or you can forward your main email address to one of them while you are in Florida. People who send you email wouldn’t have to learn a new address and many Web-based services allow you to set your main address as the “reply-to” address for emails you send.

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 PDAs, Microsoft Office 2003’s compatibility with Vista, and memory upgrades for a MacBook Pro.

My wife has requested that we get her first “PDA” and asked me for my advice on which product to buy. I am unfamiliar with the comparative features and function of BlackBerry and Treo. What would you suggest?

Well, first of all, both of these products are primarily communication devices — they make phone calls and fetch email, in addition to performing the functions of a Personal Digital Assistant. So, if she really just needs a PDA, I’d avoid both of them and get a cheaper Palm PDA that isn’t a phone or email device. The $99 Z22 would do the trick, and, unlike a phone, it requires no monthly fee. However, if she wants a phone-and-email device that is also a very good PDA, the Treo beats the BlackBerry hands down. The latter is first and foremost an email device and now has a decent phone. But its calendar, address book and other PDA functions are weak. The Treo, which evolved from the Palm PDAs, is much better at these tasks, in my opinion, especially for personal, as opposed to corporate, use.

Your columns helped me select a new laptop today that should be able to run Vista Ultimate. However, although two of your columns report that Microsoft Office 2003 should run on Vista, two salesmen at Dell said it wouldn’t. Who’s correct?

A: I am, and it’s sad and troubling that Dell personnel would give out such patently wrong information. One might even suspect they were trying to sell you the newer version of Office when you don’t need it. I have personally tested Office 2003 on a Vista computer, and it runs fine. But, just to make sure, I forwarded your question to a senior person at Microsoft and he replied that the Dell people you spoke to are: “misinformed at the least.” He confirmed that Vista supports both Office XP and Office 2003 (as long as they have been kept up to date with the latest service packs) as well as the new Office 2007. One possible explanation is that the Dell folks you spoke to misunderstood your question. Dell and other companies have ceased selling Office 2003, or will soon stop doing so. Therefore, it’s possible that they were under the impression that you were seeking to buy it, rather than merely to install and run a copy you already owned. But Office 2003 is compatible with Vista.

I own an Apple MacBook Pro laptop that came with 512 megabytes of memory. I am going to upgrade to either one gigabyte or two gigabytes. I am not a gamer. Do I really need two gigabytes for running applications or will one gigabyte suffice? The biggest application I use is Final Cut Studio.

In general, one gigabyte is all a MacBook Pro needs for doing common tasks such as email and Web browsing, word processing, music playback and simple photo and video editing with built-in programs like iPhoto and iMovie. However, Final Cut Studio is a massive video-production program meant for professionals, and it demands lots of memory. In fact, Apple’s Web site for the latest version of the product suggests between two gigabytes and four gigabytes, depending on the content you expect to edit and produce. So I would go with two gigabytes, or even more if your model of the MacBook Pro can handle it. In fact, if you are more of an amateur, I’d consider the lighter-duty Final Cut Express, which Apple says does fine with one gigabyte and can handle high-definition content with two gigabytes.

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

There’s no other major item most of us own that is as confusing, unpredictable and unreliable as our personal computers. Everybody has questions about them, and we aim to help.

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 DOS in Windows Vista, antispyware programs for Vista and the compatibility of the new Microsoft Office with older versions.

I still use several old DOS programs. They work fine in Windows XP, which I believe includes DOS. But will they still work in the new Windows Vista?

Yes, they probably will. Actually, DOS, the old Microsoft operating system that preceded Windows, hasn’t been included in Windows for years. The early versions of Windows were built on top of DOS, so DOS programs could run as they always did.

But Windows XP didn’t really include DOS. Instead, it included some underlying code that allowed old DOS programs to run. Windows Vista uses this same approach. Microsoft says it has even run the DOS version of VisiCalc, the famous pioneering spreadsheet program, on Vista.

Certain DOS programs that require something called “real mode” — direct access to the computer’s hardware — wouldn’t run properly in XP and won’t run properly in Vista, either. But, if your DOS programs run fine in XP, they will likely run fine in Vista.

I recently purchased a new Windows computer with the Windows Vista Home Premium operating system. Do I need to install a third-party Internet security program or is the included Microsoft Security Center adequate?

Despite its name, the Security Center isn’t actually a security program. It is a monitoring feature of Windows that tells you the status of your security programs. Vista does include two important security programs: a firewall; and an antispyware program called Windows Defender. It doesn’t include an antivirus program. I strongly advise you to buy and install a Vista-compatible antivirus program. You may also want to consider buying an antispyware program that is rated higher than the included Windows Defender, such as Spy Sweeper (webroot.com) or Spyware Doctor (pctools.com).

I teach college courses online. My laptop is three years old and I was thinking of buying a new one this year. I am worried about the compatibility of the new Microsoft Office with older versions. Many students are using older computers to do their homework. I need to be able to open all documents they send me and vice versa.

It is true that the standard file format in the new Office 2007 can’t be read by older versions of Office, unless the users of those older versions install conversion software. However, there are two reasons why this shouldn’t be a problem with your new laptop.

First of all, buying a new laptop doesn’t mean you also have to buy or use the latest version of Microsoft Office. The 2003 version of Office for Windows can be installed and used on a new Windows Vista laptop, if you still have the original disks. Secondly, even if you do switch to the new Office 2007, you can set it to always save your files in the older formats.

* * *

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.

Corrections & Amplifications:

The anti-spyware program produced by PC Tools is named Spyware Doctor. In an earlier version of this column, the product was mistakenly referred to as Spy Doctor.

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