Sounds like you have a virus. These 2 threads have info & advice
http://www.gnutellaforums.com/showth...threadid=39612 http://www.gnutellaforums.com/showth...threadid=41432
The second thread has advice about AV programs & a link to norbiesworld. If you can't get rid of the virus, he'll be able to help you
Make sure that you have a good, up to date AV program & that you scan a file before opening it!