hey, yer it sounds like its your grafix card. Its because the card is gettin 2 hot (the piplelines heet up and **** up). Chek you grafix card, and make sure that the cooler on it is attached properly. If it is, make sure that the fan is running when you turn on the comp. If its really broken, you can get a replacment Heatsink + Fan for the 9800 series, (ive got 1), they help ALOT with overclocking. But i would advise that you 1st try and return i if it turns out that the cards fan isnt working.