Protecting Your Computer

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 software firewalls, purchasing a computer with Windows Vista and using the Firefox browser and Thunderbird email.

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

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An IT director for a local bank told me I didn’t need ZoneAlarm since I was using a router which acted as a hardware firewall. What is your opinion?

Some routers — the boxes that direct Internet traffic on a network — do include hardware-based firewalls that can help protect computers from hackers and other intruders. But I believe that everyone should also use a software firewall like ZoneAlarm, because you can’t be too careful where security is concerned. You should at least turn on the free, built-in firewall that comes with Windows or with the Macintosh.

I was wondering if you know when and where I can purchase a Windows Vista computer?

You can’t — yet. Vista, the new version of Windows coming out this year, won’t be available on new PCs until around October. When it launches, it will be available everywhere Windows PCs are sold. At roughly the same time, you’ll be able to buy Windows Vista software in a box and upgrade existing PCs, if they are beefy enough to handle Vista’s new features.

I am switching from dialup to Verizon DSL next Saturday. Can I continue to use the Firefox browser and Thunderbird email?

Sure. Changing the way the Internet comes into your home shouldn’t change the software you use. Even if Verizon provides you with different software, you can still use your favorites. You may have to change some settings and set up Thunderbird for your new Verizon email address, but the software will work. In the past few years, I have used several different Internet services at my home and used the same software with each.

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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.

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