Dell XPS 630i Crashes

Hi everybody,
For a while now I have had a problem with my computer that hasnt allowed me to play any games, specifically Starcraft 2. Whenever I proceed to start up SC2 this screen with come up:
After this comes up I am unable to do anything, but shutdown and restart my pc. At first I thought it was due to my graphics card overheating, but that turned out not to be the case because I could kill my pc within a min or two without the graphics card even getting significantly hot.

I have a Dell XPS 630i pc, with a NVIDia GeForce GTX 280 graphics card. So far I have replaced my graphics card, and motherboards ,in that order, with neither correcting the problem.

One possible problem I thought of was that because I replaced my graphics card first, might that new one have been fried by the old motherboard as well? Just a thought.

Comment on what you might think the problem could be or any solutions, thanks for your help.