It sounds like a virus. See these 2 threads for info
http://www.gnutellaforums.com/showth...threadid=39612
http://www.gnutellaforums.com/showth...threadid=41432

Point 4 in the second thread deals with it. Also contains a lot of good advice & a link to norbiesworld. If you go to the site & register, he'll be able to help you fix the problem.