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.

If I buy a PC with an AMD processor instead of an Intel one, will I run into any compatibility issues with common software like Vista or Office 2007?

No, as long as the AMD processor, and/or its accompanying graphics and other chips, called a “chip set,” are rated as being able to handle the graphics in the version of Vista you are buying. Each chip company makes some low-end models that handle certain tasks more slowly than their mainstream or top-of-line models. And gamers are often particular about which chip sets they buy. But, in my experience, roughly comparable AMD and Intel processors and chip sets are equally compatible with common software like Office and Windows.

I have been using the Netscape Web browser for years. I am interested in shifting to using the Firefox browser. How do I transfer my extensive list of book marks from Netscape to Firefox?

Firefox will import your Netscape bookmarks automatically during the installation process, just as it can automatically import bookmarks from other browsers like Internet Explorer, Safari and Opera.

Friends who use Macs tell me they have a removable backup device that backs up their entire hard drive, including programs. Is there something similar for PCs?

You appear to be referring to Time Capsule, which is an Apple hardware product that combines a hard disk and a wireless base station and is meant to work with the Mac’s built-in Time Machine automated backup feature. The answer is that there are many backup drives for Windows PCs, and that lots of them work with Macs as well. All the major hard-disk makers sell external hard disks that connect to a PC either directly, or over a network, and which come with relatively simple backup programs. Some of these programs will do complete, automated backups of everything on your PC, including applications. Even Apple’s Time Capsule can be used to back up files from Windows PCs, though it doesn’t come with Windows backup software, and setting it up for Windows is slightly trickier than doing so on a Mac.

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