Hi, i am having a problem with my graphic card. i was just chatting on facebook and out of no where, my windows aero went out. after about 2 minutes it came back. then i opened evga precision and riva tuner and saw an option missing that can adjust the shader clock (which used to be there before). then i ran call of duty 6 and it was running just fine and the temperatures were normal. i have tried restarting my computer but the persists. please tell what should i do in this case. (please note i have never overclocked my graphic card). thankyou.