What part of my PC broke?

alienorange

Prominent
Jul 10, 2017
2
0
510
So, a few nights ago, my GPU drivers crashed. I hadn't ever dealt with a GPU driver crash like this before, so I panicked, turned it off, and started investigating. I couldn't find any visible issue with my GPU, but I did notice a burnt smell when I was leaning into the tower, though I couldn't pinpoint where it was coming from. Anyway, now my PC is running like trash, and I can't exactly figure out why.

Specs:
Nvidia GeForce GTX 970
Intel Core i5-4460
ASRock H97M Pro4
8GB DDR3 RAM
650W Supernova EVGA G1
Windows 10 x64 Home Edition

So, my brother and I both thought it was thermal throttling, because I had pulled the heatsink off of the CPU to blow dust off, and the thermal paste was dry. I cleaned it off and reapplied it, but there was not really any change.
-I tried the GPU in a different PCI-E slot.
-I tried a clean reinstall of the GPU's drivers.
-I tried to update my mobo but it failed. Same with a windows update. I don't imagine it has anything to do with either of those, though, because it was running fine before with the BIOS and windows version that I have.

I'm not really sure what it is at this point. I am thinking that my PSU may have fried, but I don't imagine it would still be running if it had. Both CPU and GPU usage jump to about 100% when I launch games, like Fallout 4 or the Witcher 3, both of which I was running with excellent frames beforehand. I now net around 15 frames max in either of those games, and that's only when I'm staring at the ground, or a wall. I've also noticed that disk usage in my HDD (where steam games get installed, my SSD has my OS) spikes to ~100% almost any time that I access it, when steam is updating / installing, or when I try to run a steam game installed there.

Any help is appreciated. Thank you.