Well, the CPU score looks fine. I guess the graphics scores are ok (I'm not sure how a 9600GT is supposed to perform). At any rate, that system should be doing a lot better than it is.
Here's what I'm wondering. You tested your ram and I highly doubt the GPU & CPU is causing the errors. I wonder if the 9600 is causing extra strain on the power system OR if the HD is going bad. Corruption off the bat is worrisome. 3DMark runs fine, just not games. It seems it could be the HD, CD drive, MB, or PSU (I know that doesn't help at all).