Q In a recent column, you wrote about cleaning off a hard drive with an "erase" program before getting rid of the computer. But I've been told that none of those programs really cleans up the hard drive, and that the only real way to get rid of your data is to destroy the hard drive. While I find that too aggressive, I'm also very nervous about someone getting my personal information. Any more suggestions?

PAM INGERMANSON, TUCSON, ARIZ.

A In theory, there are flaws in older erase programs that use Department of Defense technology to overwrite existing data. Here are some alternatives:

You could buy a "degausser" to demagnetize your hard disk, but they cost thousands of dollars (see tinyurl.com/6bn7c4h.)

You could find a PC recycling firm in your area that will shred your hard drive.

You could destroy it yourself, but that poses problems. If you drill a hole in the drive, that leaves the rest of the data intact. If you smash the drive with a hammer, only some data might be damaged. If you burn the drive you might only release noxious chemicals without ever knowing if you had eradicated the data.

The best solution may be to try a University of California erase program that uses a newer approach to disk cleaning that's called "secure erase." Find the free download at tinyurl.com/2xoqqw.

Q My four computers all get redirected when we use them for Google Internet searches. First the search takes me to a Google page with lots of items, but when I click an item I'm redirected to an alternate website. When I close the redirected website and click my original item, I'm then taken to the correct site. I know this is caused by malicious software, but my Norton security software and the Malwarebytes program you recommend can't find anything. Could this be caused by my new wireless printer?

DAVID HAYES, OTTAWA, ONTARIO

A Your printer's not to blame. Your PCs have been infected with what's commonly called the "Google redirect virus." Symantec, the company that sells Norton security software, says it's really a Trojan horse, a malicious program that masquerades as a useful one. The Trojan, which Symantec calls "Backdoor.Tidserv," displays unwanted ads, redirects your browser from legitimate search results to potentially malicious Web pages, and keeps the PC vulnerable to other harmful downloads. You can find Symantec's explanation and a free removal tool for the Trojan at tinyurl.com/ksmcdu. Click the arrow next to "download removal tool."

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