Every now and then I get an e-mail from someone asking, "Why did you send me an e-mail with a virus?"

This is interesting for several reasons. Sometimes they aren't very nice about it. More important is that fact that I had not sent any of these people anything at all, let alone a virus. Often I don't even know them. So, what happened?

In order to understand this, it is necessary to understand how some of these e-mail viruse work.

Average Joe Computer User gets an e-mail with an attachment. Since the return address is familiar to him, and the message says something like, "See the attached file for details" he clicks on the attachment. Nothing happens. He shrugs, deletes the message and forgets about it.

Unknown to him, his computer is now infected with a virus. It accesses his address book in Outlook/Outlook Express. It replicates itself and sends a copy of itself to everyone in the address book.

More importantly, it also uses some of those addresses as return addresses in the infected e-mails that are being sent.

Now, as the host/moderater of a popular blackjack website, my e-mail address is in a lot of address books. So, I get these messages, despite the fact that I'm using an operating system that these viruses won't even run on.

Conclusions:

1. Never open any e-mail attachment unless it is something that you have specifically requested that individual to send to you. The fact that the "from" address may look familiar means absolutely nothing.

2. Run anti-virus software and keep the definitions up-to-date. Most AV programs have a function to scan particular files. Usually, this simply involves right-clicking on the attachment and selecting "Scan with Norton AV (or whatever).

3. If you do get an infected file, do not blame the apparent sender. That person probably had nothing to do with it.