My computer continuously turns off whenever anything graphically intensive happens.
This started about a year or two ago intermittently, gradually getting worse over time, and now it's gotten so bad that I can't even watch videos or browse pictures or play any game at all for more than 20 seconds.
Originally it only happened when having multiple instances of World of Warcraft open, so to avoid the problem I just stuck to one instance of it, and everything seemed fine, I could play any other game on ultra settings and there would be no problems at all, just when I had two windows of WoW open.
Recently the problem has gotten very bad after switching to a new HDD. It seems that whenever I change hardware in my computer to diagnose the problem, it appears to get much much worse, in the past, I thought maybe my PSU was going bad, so I bought a replacement and the problem seemed to get even worse with the brand new PSU until I switched back to my old one.
There are no bluescreens or errors popping up before my computer turns off, it's just like someone flipped the off switch or pulled the plug on it.
I have a fresh install of Windows that I did about four days ago on my new HDD (When the problem started getting bad)
I disabled my GPU (GTX 760) and tried watching a few videos with onboard graphics, and the problem doesn't go away.
I stress tested my CPU and it didn't seem to cause any issues
I tested all of my ram five times with no errors.
I've cleaned all the dust from everything, nothing is overheating, my CPU / GPU sit at about 50-60 idle and when playing games they go up to 70-85, I even have a box fan that I sit up against my case to cool it down even more than it already is and my computer will still shut off.
I have the latest GPU drivers from Nvidia.
My PSU seems to be plenty powerful enough, this is my setup with a 700W PSU: http://i.imgur.com/V5Y9X4r.png
I really don't know what to do anymore; does anyone have any idea as to what the problem could be?