This may not be applicable to you, but I was having a similar problem with World of Warcraft, my main game, for this entire year. It would crash randomly, and it would always crash if I put my WoW settings above the "fair" option.
I was so annoyed by it that I literally changed out every part - CPU, motherboard, RAM, GPU, etc. Well, save one part - the PSU. It couldn't be the PSU, could it? I mean, the system turns on. Every other game runs just fine. Stress tests never crash the system or even make a dent. How could it be the power supply?
But indeed, it was the power supply the entire time. One night, after a crash, I saw, just for a split second, a message that read "connect additional power cable to GPU." I knew immediately. I switched out the power supply the next day and all has been well since.
If you really can't find a software error, its worth reverse engineering the parts until you find the issue.
Edited by Axon14 - 3/20/14 at 8:35am