http://hardforum.com/showthread.php?t=1421792. ONLY follow the instructions in the thread above after your have read the WHOLE thread and made absolutely sure the card is out of warranty!
------------------------------Peace cannot be kept by force, it can only be achieved by understanding: Eienstien
Reply to coozie7
Have you installed any new components such as a new GPU,CPU, HDD etc? if so it could be a power problem. Or you could hae heat problems especially if you have overclocked your card.