ZDNet: Tech Update: Security / Head off hoaxes
You've almost certainly received an e-mail warning you about a new virus. You know the type--one of those mass e-mails containing warnings of all sorts of dire things that can happen if the described virus or worm gets loose on your system. The e-mail goes on to list the name of the offending file, and tells you that all you need to do is delete the file, and the threat will be gone.

So you check your system, and sure enough, there in the Windows directory is the very file the e-mail warned you about. You wonder briefly why your antivirus software didn't pick up this one, but then you remember that the letter said that this one was so clever that antivirus software couldn't detect it. Guess you'd better delete it, right?

Wrong. If you actually do delete the file, you could very easily spend the next couple of hours reinstalling Windows. And that, of course, is why the antivirus software didn't issue an alert. The e-mail was a hoax, and if you follow its instructions, you could delete an important Windows file--one that's supposed to be there
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