OK, Ive fixed the issue, and really getting mad at myself for this but.
About a week ago I had my CPU overheating(which Im still fixing, actually in another thread, haha) so I sent it to some (idiot) guys, who honestly in my opinion had no Idea what they were doing.
Long story short I assumed it was overheating from thermal paste so I replaced, and it shut down again so I thought it didnt help(turns out you have to let paste burn on or something) so I sent it to these guys who claimed to be "expert" repairmen. I told them about my overheating predicament and they told me a day later they had been running my PC for a day and it hadnt overheated yet. The NEXT day without my permission they seemed to be hell bent on overheating it, so they OVERCLOCKED it to its max, and still it wouldnt overheat.
Whats funny is that they gave it back to me overclocked, and I had no idea. I fixed that about 3 days ago and now my cpu is a lot cooler.
Anyways, back to the issue at hand. This only started happening after I recieved it back from them, so I thought maybe the mobo got bumped in the car ride home or something. Wrong, they unplugged the waterbox on my watercooler to see if THEN it would overheat, and then plugged the pin cable back into the wrong power.
Apparently it needs to be hooked up to the one labeled CPU_FAN, or else the computer thinks it doesnt have any cooling for the cpu and shuts down. (Thats my theory, probably wrong)
TL;DR: The waterbox power was hooked into the wrong slot, it needed to be under the one labeled CPU_FAN.
Thanks for pointing out it was actually the mobo and not the cpu itself CMI86, like I said, Im no computer expert.