It looks likely that my earlier PC troubles were caused by a bad power supply. Thanks to Jason who pointed out that it might be heat, but since the symptoms happened right as I started it up, when all the components are relatively cool, I didn’t think it’d be heat related. I swapped in the power supply from my arcade machine, a lowly 150W, and its been humming along without crashes since. I’ve got a new power supply ordered and on the way. I won’t get a cool new case, instead I opted for a supply that was rated as being pretty quiet as well, the Seasonic Super Silencer 300W.