I built this computer that has been acting quite strange for a while now. At first it would freeze up after 10-30 minutes of playing games (Both low end, and high end games). The only way to get it unfrozen was to restart the PC. However, recently the PC started completely turning off out of nowhere, instead of freezing; and it would not turn back on for a while- The power button wouldn't work (unplugging/re-plugging in the power cord had no effect). The computer would remain to be non-functional for anywhere from a few minutes to a few hours before randomly turning itself back on with no interaction from me. (I would be doing something unrelated to the PC and it would turn on from the other side of the room, without me touching it).
A week or two ago, it turned itself off once again, but this time still doesn't work. Buttons on the case have no effect, unplugging the computer for 10+ minutes didn't help either. I even unplugged all parts except for core components, took out the CMOS for 15 minutes, and tried to power on the PC again with no luck.
There seems to be no power at all going to any of the components. The green light on the motherboard, that usually indicates it's powered, remains off. Absolutely nothing happens when the power button is pushed.
I assume the problem is a defunct motherboard, but I don't want to go buy a new motherboard and have it not be the problem so I'm checking here first. It could also be the PSU, or something else altogether.
Would the motherboard be responsible for these problems, if not then what?
How would I prevent this from happening in the future?
Is it possible to fix this problem without buying replacement parts?
..And my parts list:
CPU Cooler - Cooler Master V8 GTS
Motherboard - ASUS M5A97 R2.0