Trojan virus question

I keep getting a Trojan virus on my computer. My anti-virus indicates the virus is embedded in files which belong to my son.
He swears he is not opening up any attatchments on his e-mails, and hasn’t down loaded any new programs or anything.

Is it possible to get it from the “AOL instant messenger” he uses?

If not, what are all the ways a virus like this can be transsfered?

Can you give more information on the names and locations of the files, and the name that the antivirus software reports?

The virus always is in a “winzip” file.

Well, if they’re just in a Zip file, they can’t do anything until they’re extracted from the Zip file.

I’d need to have more information. cls is right that if their in a zip file, they’re safe until extracted. Some virus checkers can’t clean zip files. But it’s a good idea to delete the zip file in any case; it’s nothing essential to the computer’s operation.

Also, are you using Window Me? The automatic backup function backs up viruses, too, and they can’t be cleaned unless you turn it off. Luckly, most people don’t need to use the backups, so it can be ignored.