nvidia GTS 240 problems

i have been trying to figure out what is wrong with the video card because i keep getting a black screen. when i go to diagnose the card i keep getting a black screen. i have run the diagnosis on the rest of my system and everything checks out. when i run the diagnosis for the video card thats when i keep getting a black screen. is there an update or something else that i can use that can help? or am i going to have to replace my card?