I'm sorry but it sounds like you have a virus. See point 4 here
http://www.gnutellaforums.com/showth...threadid=41432

Please read the whole thread, it has great advice for avoiding virus probs in the future. See the link to norbiesworld, he can help you get rid of the problem & he's free!

Make sure you run a good, up to date AV program & scan a file before you open it