For the past couple of week my computer has been turning itself off without warning and without the BSOD. Initially I thought it was overheating since I am overclocking my q6600 pretty hard in the summer on air cooling. However, after turning my OC down to 3.0 and looking at my CPU temps while running prime 95, the tempe were fine and the PC never powered off. Just as a test, I put the OC back to 3.4 and ran prime 95. The temps were averaged around 68-70c but surprisingly the PC did not turn off. This was the point where I realized it wasn't the heat or the over clocking that was turning it off.
It seems to only happen when I play games. At this point I am thinking that my five year old power supply is starting to go on me. Maybe the Graphics card + the CPU is taking too much power for it these days. Bear in mind that I have been using the same GPU,CPU and power supply together for the better part of a year.
I am going to do a couple of more tests to make sure everything is working in my device manager and also make sure I am clean of malware and virus'. I also got an SSD a couple months ago but I don't think it's the cause.
If it does turn out to be my power supply; What is a good modular power supply to get these days? Is there one, or should I stick with the regular power supplies? I think 750w will be good enough since I will only ever use a single GPU. However, I am building a new PC when the next Intel (tock) chips come out and I will overclock both the CPU and GPU.