i recently had to replace my motherboard and was having the exact same error message with COD2 and Oblivion was crashing as well where it never had in the past. I came across this post searching for a solution to the problem. I'm using the X1800GTO. I had downloaded the newest drivers from ATI (Catalyst 6.8). The problem is not with Direct X. When I downloaded the old drivers I had used previously (Catalyst 6.4) the problem stopped instantly with both games. Go to ATI's website and find where you can download older drivers. I know 6.4 works, so I didn't try to get anymore current than that.
