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.

Recently, you reviewed some new Apple laptops whose batteries are sealed in and can’t be removed by the user. But I have had situations with some laptops where the only way to restart them when frozen is to remove the battery. How can this problem be handled if the battery is sealed in?

On Mac laptops, you can shut down the computer, even if the software appears frozen, by holding down the power button firmly and continuously for 5-10 seconds. You then wait a few seconds, press the power button again, and the machine should start up. This is different from the more common scenario where a brief press of the power button brings up a dialog box allowing you to choose to shut down or restart the Mac, or to put it into sleep mode.

Apple says there is another method you can use instead of removing a battery. Pressing the Control and Command keys simultaneously with the Power Button restarts the computer.

I live in the U.S. and when I visit Europe I have no cellphone, which makes it difficult to stay in touch during my trips. I am completely ignorant about cellphones and use a pay-as-you-go model that doesn’t work in Europe. What type of phone do you recommend I buy that I can use both in the States and abroad? I do not need a built-in camera, or any other fancy add-ons. I only want to be able to call people.

The two major U.S. phone carriers whose underlying technology is compatible with the system used in Europe are AT&T and T-Mobile. Given your needs and your usage pattern, I’d go into one of their stores and look for the least expensive and simplest model that can operate on all the frequencies used in the U.S. and Europe. These phones are typically referred to as “quad band” or sometimes as “world phones.” I would also try and find a plan that minimizes overseas roaming charges, which can be quite high.

Another option is to look for an “unlocked” phone that can accept different SIM cards, the small chips that connect phones to carriers. That way, you could have one SIM for use in the U.S. and another for whatever country you are visiting.

I have hundreds of folders in “My documents.” In each folder there may be hundreds more individual files. Is there a way to rapidly search for key words in all of those documents in order to locate any files that might contain a particular word?

If you are using Windows XP, you can download and install various desktop search add-on products that can solve your problem. The best known are Windows search, from Microsoft, at http://bit.ly/Dflai, and Google Desktop Search, at desktop.google.com. If you have Windows Vista, it comes with a built-in desktop search function that can accomplish that task, though you can also use the Google product.

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

I am utterly fascinated with the iPhone. Dying to get one. I’ve been a Verizon Wireless person for 15 years and have never had a coverage problem in the metro Boston area. I don’t hear great things about AT&T’s 3G. Do you think it’s worth the switch?

While I believe the iPhone is a marvelous device, I have always advised that nobody should get any phone unless it is on a network that they are sure works to their satisfaction in the areas where they will use it. Personally, I find AT&T’s network adequate where I use it, and getting better, so I am happy with my iPhone. But there are many others who have either given up their iPhones out of frustration with AT&T, or who have decided against buying one because they prefer another carrier, or want to avoid AT&T.

So, my advice is to ask friends around Boston who have iPhones or other AT&T 3G devices how they feel about the network. You might also enter your ZIP Code at some Web sites that track overall carrier coverage and dead zones, like cellreception.com, or deadcellzones.com.

If this research suggests you should avoid AT&T, but you are still “dying” for an iPhone, you might consider the iPod Touch, which is essentially an iPhone without the cellphone inside. It lacks the iPhone’s camera, GPS and built-in microphone, but it does connect to the Internet via Wi-Fi and runs the vast majority of iPhone apps. It doesn’t carry any monthly fee or require a carrier contract.

How do I forward an email from Gmail? I don’t see any icon for forwarding messages like I do on other email programs.

Gmail hides a bunch of menu choices under the Reply icon in the upper-right-hand corner of open emails. If you click on the small downward arrow next to the Reply icon, you will see more actions you can take on the message, including Forward, Reply to All, Print and others.

I read your recent article on IE8 and installed it on my desktop. I did not notice in your article any mention of IE8 slowing the computer down significantly, but it has had this effect on my PC. Why didn’t you mention it? Can I uninstall IE8 and return to the prior version?

I didn’t mention the problem you are having because I never observed that Internet Explorer 8 caused any general slowdown of any of the multiple Windows PCs on which I tested it. I did warn that IE8 itself grew sluggish when it had a large number of Web sites open simultaneously in tabs, but, in my tests, even that didn’t slow down the whole computer.

However, you can indeed uninstall IE8 and return to the previous version. Microsoft has provided complete instructions, and even an automated uninstall program, at: support.microsoft.com/kb/957700.

• 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 get confused by all the different models of the BlackBerry — Bold, Storm, Curve, Pearl and so on. Can you briefly explain the differences?

There are too many models to list here, because RIM, the maker of BlackBerry, makes varying versions for competing wireless carriers, and these may have different features, even if they look the same. However, here’s a quick breakdown of the main flavors.

The Bold is the top-of-the-line BlackBerry, relatively large and costly, with a wide keyboard and a big, vivid screen. The Curve is its little brother — still sporting a good, full, keyboard, but lower-priced, smaller and lighter. The newest Curve, called the 8900, has a beautiful screen and is even sleeker than its predecessor.

The Pearl is a slimmer, low-priced, more fashion-oriented model with a truncated keyboard that has two letters on each key and relies on software to guess which one you meant to hit. The Pearl Flip is much like the Pearl, except, as its name implies, it’s a flip phone.

The Storm is the BlackBerry line’s most direct competitor to the Apple iPhone. It’s the only BlackBerry without a physical keyboard, instead relying on a large, beautiful touch screen for typing and navigation. Unlike on the iPhone, however, the Storm provides physical feedback each time you press down on the screen.

I’d be interested in the new, tiny iPod Shuffle, except that I dislike Apple’s earbuds. And, because they have now moved the playback controls to the earbud cord, I can’t use my favorite third-party set. What are my options?

Well, one option is to buy the old model of the Shuffle, which Apple is keeping on the market. It’s larger, but still very small, and has the controls on the player itself, rather than on the earbud cord, so you can use plain old earbuds or headphones from other companies. Plus, at $49, it’s $30 less, though it has only 25% of the capacity of the new one and lacks the new model’s voice features.

Another, costlier, option is to buy better earbuds that have the new controller built in. Apple sells a pair of $79 in-ear buds with a control module on the cord. They were designed for the iPod Touch, but the company says they work perfectly with the new Shuffle. Several other headphone companies, such as Klipsch, have announced plans to offer either headphones or adapters with Shuffle-compatible controls in coming months.

Is it safe to upgrade my Vista PC to the beta version of Windows 7?

Since it is a beta version, there is always some danger of problems. But I have upgraded a couple of Vista computers with no special tricks or help, and with no significant problems. Still, there are a couple of caveats. First, Microsoft will be replacing the beta with a more polished “release candidate” that could involve a re-installation process, so you may want to hold off. Second, Microsoft isn’t guaranteeing that every hardware feature on every computer or peripheral will work properly under the pre-release versions.

• 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.

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 need to use Microsoft Publisher documents on my MacBook. Unfortunately, I can’t figure out how to do this. I have tried to run it on Microsoft Word, but this didn’t work.

As far as I know, neither Microsoft nor Apple nor anyone else makes a native Mac program that can open or edit Microsoft Publisher documents, which use their own special format, rather than any common cross-platform format.

However, there may be some workarounds. If you own or can borrow a PC and a copy of Microsoft Publisher, you could export the documents as PDF files from within Publisher, and then open them on a Mac. Or you could run Publisher itself on your MacBook, since Macs can run Windows and Windows programs, if you buy and install Windows.

Your Mossberg Solution column recently recommended an add-on for Firefox called Surf Canyon that improves searches. But I am wondering if it’s safe to use, since it is labeled “beta.”

I have been using Surf Canyon in Firefox for months, without any problems. (It also works in Internet Explorer.) You are correct that it’s a beta, but that label doesn’t usually mean a product is unsafe, just that it’s incomplete or unpolished. In the old days, a “beta” product was usually pretty flaky and available only to a very small number of testers until the kinks were worked out. Now, especially with Web-related products, a “beta” is often just another word for version 1.0 of a product. It is open to all, and may not work perfectly, but is usually not dangerous to your computer.

Is there a legal way to use a smartphone as a modem for a laptop?

Yes, indeed. It depends on your carrier, and your plan, and your phone, but it can be done, perfectly legally, either using a cable or Bluetooth wireless to connect the phone to the laptop. Note that, depending on your plan, the carrier may well charge you an added monthly fee for this privilege. Also, the speed of your connection may be a bit slower than the speed you’d get from a cellular data card you insert directly into the laptop or from one that’s built in.

• 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.

Last week, when you wrote about the ChaCha cellphone search service, you didn’t say how they make money. Are they collecting phone numbers from customers so they can send spam text messages, or sell the numbers to others who will do so?

ChaCha allows you to ask any Web-searchable question, by speaking it or texting it over a mobile phone, and then it sends you the answer via text message. The company charges consumers nothing, but says it is hoping to make money by striking deals with cellphone carriers to incorporate the ChaCha service into their current 411 phone-number look-up services. Also, it hopes to eventually include ads in the text message answers it provides.

In addition to the message that includes the answer, ChaCha sends you a message saying it is working on your request and restating your question, so you can see if it understood you correctly. It also sends an introductory text message to first-time users and occasional tips on how to use the service. Scott Jones, ChaCha’s chief executive, asserts that “we do not spam” and “we never make phone numbers and/or email addresses available to others.” He said the company is updating its privacy policy to make that clearer.

We have DSL service. I use several Web-based applications, one of which is online backup, and my husband is concerned that they degrade his use of the Web, which includes creating Web sites. I contend that that is like saying turning on one light bulb is using too much electricity, that two people on one DSL line aren’t using up too much bandwidth. Who is right?

Every situation differs, depending on exactly which programs you are each using, how you have them set, whether you are using them simultaneously, and how fast your DSL connection is. However, in general, your husband is correct that it is possible for heavy Internet usage on one computer in a home to slow down Internet speeds on another.

This is especially true with something like online backup, because it relies on your DSL account’s upload speed, which is typically far slower than the download speed. If your online backup program is trying to push a bunch of files over a slow upload connection, while he is in another room trying to upload new versions of a Web site over the same narrow upload pipe, it could affect the speeds he gets. You might try coordinating or staggering those online activities that involve heavy uploading. Normal Web surfing or emailing shouldn’t require any such coordination.

I am thinking about purchasing a Dell (DELL) XPS One all-in-one desktop, but I have one question. Does the Dell’s built-in TV tuner require any extra attachments to watch TV right out of the box?

You can watch over-the-air stations and analog basic cable stations right out of the box, without added equipment. However, you may want to connect a small desktop antenna to improve reception, which is what I did when I tested this machine. To use the XPS One with digital or premium cable or satellite stations, you would have to connect it to a cable or satellite receiver, just as most people do with their TV sets. This requires the use of an adapter that comes with the machine.

• 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 am considering the purchase of the MacBook Air (AAPL). If this computer freezes up, as my current Dell Inspiron does on occasion, how would I correct for that? I usually remove and then replace the battery on the Dell (DELL). But what would I do if this happens with the Air, since it has no removable battery?

You can force a frozen MacBook Air — or any current Mac laptop — to shut down and restart without removing its battery. You just hold down the power button for a few seconds until the machine shuts off, then wait a few seconds, then turn it on again.

I am a Verizon (VZ) customer and have a Palm (PALM) Treo 700W for personal use. I would like to replace the Treo but, in light of Verizon’s announced “open network” policy, I am wondering if this is the right time.

It’s far too early to know what new phones will be available under the new Verizon program, since that depends on which phone makers decide to make devices to run on the “open” network, and what kinds of devices they might produce. There is the potential for phones that are more creative or interesting than what is available today, but it’s only a potential. Verizon has just laid out the first details of the plan, and no product announcements are likely for quite a while. If your Treo needs replacing soon, and you want to remain a Verizon customer, you will have to choose from the company’s current smart-phone offerings.

Are there any cellphones that allow for two separate phone numbers? Right now I carry two devices, both with the same carrier.

At least in the U.S., each cellphone, or each SIM card that goes in a phone, is normally tied to a single number. To use two numbers on a single phone, you could purchase an unlocked phone running on a GSM network and then purchase two SIM cards, each with a separate number, and swap them in and out. But that would be an inconvenient process, since inserting and removing SIM cards typically requires opening the phone and even removing the battery.

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 have a USB cell phone data card that I use with my laptop. This card offers me world-wide connectivity wherever there is GSM cellphone service available. Is there an adapter that will allow me to use this card with the iPod Touch?

I know of no such adapter, nor of the software that would be needed to make one work. However, although the iPod Touch has no cellphone capability, it does include Wi-Fi, which can give you high-speed Internet access world-wide whenever you are in range of a Wi-Fi wireless network.

What U.S. cellphone service provider should I consider when purchasing a new contract and phone that can be easily used in most western European countries and also get good coverage in the U.S.?

In the United States, the only two major carriers that use the technology compatible with European networks are AT&T and T-Mobile. As to which has better coverage in the U.S., my own anecdotal experience is that this varies greatly depending on where you are, and that neither has coverage that’s as good as Verizon’s in as many major cities. However, Verizon (like Sprint) uses a technology that isn’t compatible with European networks, though it has one or two phone models that include both technologies.

I have just switched to the Mac from Windows. Is there a tutorial somewhere on how to use the Mac user interface and operating system?

There are a couple of books on switching to the Mac, which you can find at online bookstores. Also, Apple maintains two free, illustrated online tutorials called “Mac 101″ and “Switch 101,” the latter being specifically for former Windows users. They are available at apple.com/support/mac101 and apple.com/support/switch101.

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