No advanced graphics

I replaced the motherboard on my Gateway Gt5220 this summer after the mb mysteriously fried, then had the power supply replaced from a local computer shop. Since the replacement though, the high level graphics won't work as well as the graphics on the dvd player. Is it possible that he hooked up wires incorrectly when he replaced the power supply, or that I hooked up wires incorrectly to the mb when I replaced it. I was very careful to note which connections went to which pins.

Gateway was absolutely no help although the computer was just out of warranty. I appreciate any help!