OS: Windows 8.1
CPU: AMD Athlon II X4 620 2.6ghz quad core
RAM: 4GB (2x2GB) DDR3
System drive: Crucial M4 128GB SSD
Motherboard: 2nd-hand Acer FRS780M OEM board
GPU: XFX Radeon HD 5770 1GB DDR5
PSU: Thermaltake TR2 500W (don't worry, it's not the infamous terrible Thermaltake model)
This has started happening more and more often. It used to be once a month, now it's more like once a week. I typically leave my computer on 24/7 (I would let it go to sleep when idle but for some reason it won't, something is resetting the idle timer), but sometimes I will come in and find my computer turned off - when I boot it up, there are no "your system has recovered from a serious error" messages, although I don't know if Windows 8 even does that. When I start up my browser it says it wasn't closed properly and asks me if I want to restore my open tabs. It almost never happens while I am using the computer, I think it only ever happened once while I was using it. I always come to find it turned off as though there was a power failure in the house - but there wasn't, otherwise my clocks would be reset. It just happened again a few minutes ago, but this time, my desktop icon layout was scrambled, like what happens when the resolution changes back and forth. Now I have to go back and rearrange them all.
My system is pretty old and crappy, I know. I haven't upgraded it because it still lets me play almost all the latest AAA games at med-high settings at 1080p at 30-60fps. But I really don't think this is the power supply. The PSU is less than a year old, I bought it recently because my last one failed. But I'm guessing that something is starting to fail. It probably doesn't help that this computer runs on the floor of a sometimes-damp, very dusty basement. I do vacuum it very often though, I never let the fans collect much dust. But my point is that something could be corroding, maybe on the motherboard. Does anyone know what I should be looking for, or what component other than the PSU failing that could cause this to happen? Or at least what I can rule out? Burst capacitors on the motherboard, or corroded traces? The GPU? The CPU itself failing? Should I do a RAM scan? My SSD?