My PC keeps shutting off while playing. Not BSOD, just powering off, like the power went out. I've used this PC for hours on end and it never crashes like this, only happens while playing Halo 2. The inputs from my controller also bug out for a second or 2 before shutting off. It acts like I'm holding down whatever inputs I was pressing right before it crashes, even if I let go of the buttons. It didn't do this when I was playing a few days ago, just started last night.