I am Currently using a Intel 945pl-s3 mobo with core 2 duo e6400 @2.13Ghz and Geforce 7900gtx which is quite old, so I bought 9600gt but when I install it and run any game (even old Call of duty 1) the picture freezes, and a few pixels change colour, the sound continues to play for a few seconds, then freezes, making a buzzing sound.
I've Tried it in another computer and it works fine, I've tried swapping my ram but that doesn't help either.
either your PSU is dying, or you got a faulty vid card
"Tagan 430watt, But i tried in another pc with 300psu and it worked fine with that. " but your psu may be faulty..... Id say thats the most likely thing sing you just went to a higher powered card
did you update to newer drivers!?!?!?! or just use the ones that were already installed???... if you didnt get new drivers they're probly from before the 9600gt was even released... any causing you issues.
go to geforce website and download drivers for your card