It's most probably a virus. Have you downloaded any files of 851.7 KB?? There's some info here
http://www.gnutellaforums.com/showth...threadid=39612

And this thread has more (point 4). There's also a link to norbiesworld... if you can't get rid of the virus then he'll be able to help you out.
http://www.gnutellaforums.com/showth...threadid=41432

Please read all of the 2nd thread, it's full of good advice. Always have a good, up to date AV program & scan a file before you open it!!!