Vid card problem?

[Judd Sandage]

I have an ATI 9600pro and I have been getting random lockups while playing doom3, farcry, joint opps, and BF1942, I kinda thought it was the motherboard, but no amunt of tweaking will get it to stop, I have 2x512 corsair xms sticks, Gigabyte 8KNXP ver 2.0 mobo, p4 3.0c, and the coolermaster power 6 HSF on the CPU, audigy2 platnium. now I did replace the HSF on the GFX card about 6 months ago when the origanl on kept screaming, but I cant remember if the lockups started at the same time.... I had changed the mobo at that time aswell, if it is the GFX card what would be good in the $200 rangw to replace it? tho I am looking at somthing faster, I might even go so high as to get a 6800 if I can find one cheap enugh