Try steps 3, 5 & 6 here Fixes for Limewire (click on blue link) Try them one by one starting with point #3 (deleting LW preferences.)

Oh the sample image for point #3 is here http://www.gnutellaforums.com/window...tml#post183932

BTW do you have Alcohol on your computer? Or have you made any changes to your video card settings, or installed anything recently before these problems started to happen?