I'm no expert here... but your problem does look like it's from a virus.....obviously you couldn't scan your computer for virus when your antivirus software is an '.exe'
Have you tried scanning your computer for virus from DOS? the virus may be one of those that work only in windows and not in DOS so you could probably run your antivirus software from DOS...
incase you do not know how to use DOS...sorry...I can't help you....(I usually call my Dad).... but you can send an email to your antivirus software's page... and ask them to send you the full instructions...I am sure they'd be glad to help.... Or, you can reply to this message, telling us which antivirus software you are using, and also what operation system (windows 95/98/Me/XP/...?) and hopefully a true expert will be able to help you.
