Bill Gates doesn’t want to sell you a Nieman-Marcus cookie, and Melissa doesn’t love you.

Microsoft isn’t planning to mail you a free sweatshirt. A band of roving thieves isn’t likely to attempt to harvest your kidney while you sleep. There’s no lunatic in the parking lot who wants to spray you with toxic eau du toilette. And if you read this article, your head won’t explode.

Some days my e-mail in-box is clogged with news about seemingly impossible threats to my health, safety and sanity. Only a tiny fraction have any basis in truth. How can you find out if the warning is legitimate? Fortunately, there are ways to uncover the truth behind “news” about underarm deodorant (no, it doesn’t cause cancer) or aspartame (not exactly a health food, but not as dangerous as some e-mails have claimed).

Before forwarding an alert to anyone, simply use a reliable search engine such as Google. Type in query terms such as “headlight” and “hoax.” (Do you remember the yarn about the gang initiation rite, which fooled even the police? A quick search in Google pointed to several sites that debunked this chilling urban myth.)

Of course in recent months, corporate computer systems and home PCs alike have been crippled by genuine viruses. Remember ILOVEYOU and Melissa? When someone sends out troublemakers like these, we have to take action, and it’s great to be forewarned. It’s too bad that some creepy people with too much time on their hands also make up virus warnings.

If you receive any e-mail that encourages you to “send this to everyone you know,” it’s probably bogus. Most legitimate warnings don’t advise you to bombard your friends’ mailboxes. The problem is that well-meaning people will sweetly comply and forward these notes to everyone in their address books.

If you want to check out a virus warning, go to the Symantec web site, which contains up-to-date information on viruses that pose a genuine threat.

Word to the wise: Never open an attachment—especially an executable file—that you weren’t expecting. Recently I received worm from someone. She didn’t even e-mail the file to me, but there it was, sent to me automatically by the worm in her system. Since I wasn’t expecting an executable file (which doesn’t run on my Mac anyway), I smelled trouble. What to do? Trash the file and alert the apparent sender.