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.

A: Sadly, Microsoft killed Outlook Express—its free, fast and simple Windows email program—long before Windows 7 came out. In Vista, it was replaced by something called Windows Mail. Now, there’s no email program at all built into Windows 7, unless a PC maker chooses to include one. But Microsoft offers for download a free product called Windows Live Email that is the latest successor to Outlook Express. You can get it, alone or as part of a suite of free “Essentials” programs that used to be routinely part of Windows, at: windowslive.com/desktop.

I was told that Apple is developing its own version of the Kindle e-book reader. I wanted to purchase a Kindle for Christmas, but now I’m not sure whether I should wait for an Apple version.

A: I have never heard any Apple official say or hint that the company is developing a direct competitor for the Kindle, or is planning to make any dedicated e-book reader. What you may be referring to is that some Web sites have been speculating that the much-rumored forthcoming Apple touch-controlled tablet would be mainly intended to be an e-book reader. I haven’t any evidence of this either.

The iPhone and iPod Touch already can run a free Kindle app from Amazon that allows you to read Kindle e-books on those devices without needing to own a Kindle itself. And Barnes & Noble, which has also announced a dedicated e-reader, has a similar iPhone app. So I assume that any general-purpose Apple tablet would likely be able to run such an app as well and function as an e-reader—along with performing other tasks.

But that’s different than producing a dedicated reader with a screen and controls designed primarily for book reading and a companion electronic book store, something Apple currently lacks. It’s entirely possible Apple is going into the e-book business, but I know of zero hard evidence that this is the case.

Do you have any recommendations about switching an existing 64-bit laptop from Vista to Windows 7? I totally dislike Vista but I don’t know if the switch can be done.

A: Yes, it can, in most cases, unless your PC’s manufacturer for some reason isn’t supporting or recommending the upgrade of your particular model. Just make sure you get the comparable version of Windows 7 (say, 64-bit Windows 7 Home Premium if you are currently using 64-bit Vista Home Premium) so you can do a direct, in-place upgrade that will allow your programs and files to remain in place.

You can also do an in-place upgrade if you opt to move up to the costlier Ultimate version. I would also advise backing up your irreplaceable personal files before you begin the process.

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

Write to Walter S. Mossberg at walt.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.

In last week’s Mailbox, you said that Windows XP machines can slow down over time unless you do “a lot of techie maintenance.” What did you mean? I regularly defragment the hard disk, tweak the registry, and clean out temporary files, but my PC is still slow.

All of these things are helpful, though I don’t recommend that nontechie users “tweak” the Windows registry, which contains vital program information that can mistakenly be removed or altered if you don’t know what you’re doing. Another speed-enhancing tactic is to use a program like Startup Cop Pro (snipurl.com/b4v91) to prevent unneeded programs from running at startup, and one like PC Decrapifier (pcdecrapifier.com) to clean out craplets — unwanted pre-installed programs.

However, what I had in mind when I wrote that was something more drastic, something a number of techies I know do annually: a complete replacement of Windows. This involves first backing up all your files, and then performing what’s called a “clean install” of Windows XP that wipes out everything on the PC and starts fresh. You then would copy back all your data files and re-install your programs.

This can make the computer feel like new, but the problem is that it can be tricky and tedious for nontechie users. Depending on the source of the copy of Windows XP you are using for the clean install, you may have to locate and re-install drivers for peripheral hardware and for hardware features of your particular make and model of PC. You may run into licensing and activation issues with your re-installed programs. And you may have to download numerous patches and upgrades for Windows itself and for your programs.

I am considering buying one of the new MacBook Pro 15″ laptops. What do you think of the keyboard on this laptop? Is it easy to type on compared to other laptop keyboards? What do you think of the shiny screen?

Because keyboard and screen preferences vary from person to person, I strongly urge all laptop shoppers to try out models they are considering before buying, even if only for a few minutes at a retail store. Having said that, I find the MacBook Pro keyboard to be very comfortable and easy to use, with good key spacing and feel. I personally prefer matte screens to glossy ones, but own laptops with both types and find the glossy ones acceptable, if not optimal.

I use the Windows Mail program that came with Vista on my computer. You say Windows 7 won’t come with that program. Is there something similar that can be installed?

Microsoft will encourage people to download a similar free program called Windows Live Mail, which is closely tied to its Live online service. Or, you could switch to a competing email program, or rely on Web-based email.

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.

So it was a big deal when Apple (AAPL) announced a new service that, for $100 a year, would bring corporate-type synchronization of email, calendars and contacts to anyone. It was even better that Apple promised that the service, called MobileMe, would work on Windows computers as well as on the company’s own Macintosh computers, iPhones and iPod Touch hand-helds. To top it off, Apple threw in 20 gigabytes of online storage, a suite of Web-based applications, the ability to synchronize browser bookmarks and an online photo gallery.