Hmmm I think your problem might be your display adapter drivers.
others have had similar problems with that display adapter. They have reduced their resolution from 32 bit to 16 bit color and helped them.

You can check out this link to a post. http://www.gnutellaforums.com/showth...0&pagenumber=2


You can check this link out also they had a different solution. http://www.gnutellaforums.com/showth...5&pagenumber=4


Best of luck