There are networked hard drives from several manufacturers that can back up both laptops wirelessly and allow sharing. One I reviewed recently is the My Book World Edition from Western Digital. Another approach would be to use a Web-based synchronization service. My favorite of these is called SugarSync, from a company called Sharpcast.

SugarSync can automatically, and almost instantly, synchronize files in folders you select among multiple computers, while also backing them up to a password-protected Web account. SugarSync starts at $5 a month or $50 a year for 30 gigabytes of files, and goes up in price based on the amount you use. The company offers a free two-gigabyte account and a free trial of larger accounts for 30 days. More information is at sharpcast.com.

I have been a Windows user for may years but have wanted to change to Mac. Yet every article I read says that Quicken, which I depend upon heavily, will not run—at least reliably—on a Mac, even with the Windows-compatible software. Is this true?

The native Quicken version for the Mac is a less capable program than the Windows version, and doesn’t use the same file format, which makes importing Windows Quicken files a tedious and imperfect process for many users. Intuit, the maker of Quicken, is promising a new, much better native Mac version early next year that it claims will solve these problems, but I haven’t tested it, so I can’t verify that pledge.

However, in tests I have run periodically, Quicken for Windows ran just fine on a Mac equipped to run Windows and Windows programs. This was true when I used either Parallels or Fusion, which allow you to run Windows programs on a Mac simultaneously with Mac programs; or when I used Boot Camp, which converts the Mac into a full-fledged Windows machine, with Apple’s operating system turned off.

I plan to get a new computer after Windows 7 is released in October, to replace my old Compaq running Windows XP. Will I have difficulty moving my files to the new one?

You shouldn’t have much difficulty with your personal data files. Microsoft is building in an Easy Transfer program to move personal files to a new Windows 7 PC. But the Microsoft program won’t move over your programs. You will have to reinstall all your programs, which means finding your installation disks or installer files and re-installing all the updates from that have occurred over the years. A company called LapLink is promising to sell software it says will automate the entire process, including moving programs, to spare you this re-installation burden. But it isn’t out yet, and I haven’t tested it with Windows 7.

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

I bought a Compaq Presario notebook that came with many games that I don’t use. Can I increase the available memory by deleting all of the games?

You can increase the disk storage space that’s available to you by deleting the games, which take up room on your hard disk. But that isn’t the same as increasing “available memory.” Memory is the capacity of the computer to manage data at any one moment, and it is governed by the random-access memory, or RAM, inside the machine. Unless any of the games, or some game-launching programs, are automatically loading into memory when your PC starts up, the games aren’t wasting memory, just disk space. Getting rid of the games is still a good idea, but don’t try to do so by simply deleting them, as you would a file. You should do it by properly uninstalling them using the Windows uninstaller control panel, which is called “Add or Remove Programs” in Windows XP, and “Programs and Features” in Windows Vista.

I plan to buy an Intel-based Mac. I will need to run some Windows software for school. If I use Parallels to run Windows and the Mac operating system simultaneously, and someone does happen to get me with a Windows virus, can that migrate over to the Macintosh side of my computer?

First of all, I can’t stress enough that anyone running Windows, on any hardware — even an Apple computer — should obtain, install and run Windows security software, including antivirus and antispyware software. I do so, not only on my physical Windows computers, but on the virtual Windows computers that run on my Macs via Parallels. Even if you are using Apple’s own Boot Camp solution for running Windows on a Mac, which doesn’t allow the two operating systems to run simultaneously, you should be running security software on the Windows side. Such security software is primarily intended to protect the Windows environment on a Mac. It is unlikely that a Windows virus could migrate onto the part of the computer controlled by the Mac operating system, and even if it did, it couldn’t run there if it was written strictly for use in Windows. It could run only in the faux Windows computer created by Parallels. However, the people who write malicious software are relentless and creative, and it’s impossible to rule out anything they might try, or do. There is one danger to your Mac in this scenario. Parallels includes an optional feature that allows Windows, and Windows programs, to access folders and files on the Mac side of the machine. If you turn on this file-sharing feature, and if you get a virus whose purpose is to delete or corrupt files, it could attack these Mac files, because Windows has access to them. So, for maximum security, I’d advise that you leave this feature off. But, even if you do so, you should still obtain, install and use Windows security software for use when running Windows.

In your column last week about the Ooma device that gives you free domestic phone calls over the Internet, you mentioned that, until the product goes on sale in September, the company is giving away 1,500 free models, but only to people who have been given a special token by existing owners. Can I get one of your tokens?

Sorry, even if I had been sent enough tokens to fulfill the numerous requests I got, I couldn’t fulfill them. I am sending my few tokens back to the company, along with the Ooma gear I was lent for my testing. For ethical reasons, I don’t keep the products companies lend me for review, or take anything of value from them, including tokens entitling people to get a $399 product free of charge. Nor can I help the numerous other readers who asked me to get them on Ooma’s free distribution list.

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 Cingular data networks, the quality of Compaq laptops and options for connecting an iPod to home speakers.

In your review of the new T-Mobile BlackBerry Pearl, you said Cingular Wireless has a data network that is much faster than the EDGE network that T-Mobile uses. But I have a BlackBerry from Cingular and it, too, uses EDGE. So how is Cingular faster?

In 80 cities, Cingular has now rolled out a new network based on a technology called HSDPA that, in my tests, can be 10 times as fast as EDGE. However, most of its phones and digital devices haven’t been updated in new versions that can use the new, faster network. So far, only a few regular phones and laptop data cards from Cingular can use HSDPA. Its data-centric hand-helds, like BlackBerrys and Treos, are still stuck on EDGE, which Cingular continues to maintain alongside the new faster network.

But Cingular plans to offer new versions of the data devices in the coming months that can take advantage of the new, higher speeds. By contrast, T-Mobile has nothing faster than EDGE. Verizon Wireless and Sprint also have networks that are much faster than EDGE, based on a technology called EVDO. They are way ahead of Cingular in both the number of cities deployed and in the variety of devices that can use the highest speeds. For instance, the Verizon Treo I carry uses EVDO and can download Web pages and email attachments much more quickly than any EDGE device can.

There is a catch. With Verizon, Sprint and Cingular, even if your phone or data device can use the highest-speed networks the carriers offer, they will drop down to a lower-speed network if you enter an area where the higher-speed coverage isn’t available.

I bought a Compaq laptop in January 2005. Now in August it will not turn on. Naturally I only had a one-year warranty. The Geek Squad tells me I need a mother board, and that will cost more than a new laptop. Does Compaq have a history of only lasting a little over a year, or did I get a lemon?

Neither my email from readers nor anything I have read suggests that Compaq computers typically last only a year or so. However, reader surveys published by Consumer Reports and PC Magazine rank the Compaq brand (which is now owned by Hewlett-Packard) at or near the bottom in categories like how often its laptops need repairs and how reliable they are.

In general, I believe that as the factories in China (where nearly all laptops are made) jam more powerful and numerous components into slender laptops, quality and reliability are falling. Even Apple, which ranks at or near the top on the surveys I mentioned, is having problems with some of its newest laptops (and I am not referring here to the burning batteries Apple and Dell purchased from Sony).

Are there any good, effective options for getting an Apple iPod to work with a home speaker system? I guess I’m envisioning a “receiver” that allows an iPod to dock with it.

There are lots of products on the market that allow you to connect an iPod to a home audio system, or even just speakers. They range from simple audio cables you can buy at Radio Shack to iPod docks that connect to speakers or an audio receiver, and even wireless approaches. Apple itself makes a $19 cable and a $39 dock for this purpose and also sells a complete kit, with dock, cables and remote, for $99. But other companies sell similar products as well as self-contained docks.

There are way too many of these to list here, but there are some Web sites that can help you. Apple has a Web page listing some accessories, at www.apple.com/ipod/accessories.html. More are listed at Apple’s online store, at store.apple.com, under iPod Accessories — “Cables & Docks.” Another good source for information about this topic is ilounge.com.

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Because of the volume of email I receive, I can’t routinely answer individual questions by email, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

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 cellphones as modems for laptops, storing personal files from office computers and buying an ultralight laptop.

I would like to buy one of the new phones that run on high-speed networks from Verizon or Sprint and use it as a modem with my laptop. Do the phone carriers charge extra for this?

Yes, both Sprint and Verizon do impose an extra monthly charge for using this feature of phones like the new Treo 700p. They reason that if you access the Web on your phone, which has a limited browser and no hard disk to store large downloads, you aren’t likely to use a huge amount of network capacity. But once the phone is used as a modem with a laptop, it becomes very much like their laptop cards, for which they do charge a hefty monthly data fee. For instance, Sprint charges $40-$50 a month extra for unlimited data connections using the Treo 700p as a modem, depending on the length of your contract and whether you also have a Sprint voice plan.

I’m changing jobs after 10 years. What is the best way to take my personal files with me? I know Microsoft Office documents can be readily put on any storage media, but what about emails and contacts stored in Outlook? Can you offer some advice on how to best accomplish this move? (I am not taking any company property.)

Since this isn’t a legal column, I won’t weigh in on what constitutes personal data on a company computer. But it’s pretty easy to move your email and contacts from your Outlook to another copy of Outlook on a new PC at your home or your new office. In Outlook, go to the File menu. Select “Import and Export… “. Choose “Export to a File.” Then select “Personal Folder File (.pst).” Next, choose the Outlook folder containing the data you want to export. This could be your email Inbox, or any other email folder, or it could be the Contacts folder, or any other non-email folder, like Calendar. Finally, select the location where you want to save the exported data. If you are using a USB drive, use the “Browse” button to locate it. Then, hit “Next” and then “Finish.” Repeat the process for each folder you want to export. At the new computer, insert the drive with your exported data, launch Outlook, bring up “Import and Export…” again, and this time select “Import from another program or file.” Follow the steps to import a .pst file.

I am interested in purchasing an ultralight laptop computer for traveling, something I could carry in a messenger bag. I wish to use it mostly for Internet connectivity and word processing. I might even sneak in a DVD for use on the plane. I have looked at the Sony Vaio TX series and the Dell X-1. Are there others in the same size/weight category I should consider?

Yes. You might look at the HP Compaq nc2400 or the Lenovo ThinkPad X60 or the Gateway NX100X or the Toshiba Portégé R200. Except for the HP, none of these has an internal DVD drive, though, so depending on how important that is to you, you might have to spend more or go up to around four pounds. The Sony TX is excellent and combines low weight with an internal DVD. But it’s expensive. Other options for ultralights with internal DVD drives are offered by Fujitsu and Panasonic. I haven’t reviewed all of these, so I can’t recommend them all. My review of the Sony TX is at: http://ptech.wsj.com/archive/ptech-20051006.html. My review of the HP nc2400 is at: http://ptech.wsj.com/archive/ptech-20060518.html. My review of the ThinkPad X60 is at: http://ptech.wsj.com/archive/ptech-20060420.html.

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Because of the volume of email I receive, I can’t routinely answer individual questions by email, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

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