Nine degrees from just swapping fans is wild, especially with a $15 laser thermometer. Wait, you only swapped two fans and didn't touch the GPU cooler at all?

That bit about your brother in law saying the paste was a gimmick really got me, because my uncle pulled the same thing on me with a lawn mower of all things. He swore up and down that oil changes were a scam cooked up by the companies, and that you just top it off forever and it runs fine. So I tried it on a beat up Craftsman I got for forty bucks, ran it two summers, and the thing started knocking so loud the neighbors came over to see what was happening. Turns out the oil was basically tar and the piston was eating itself alive, which is real close to what your Athlon was doing at 92C. Some guys just can't admit the boring maintenance step is the whole reason the machine lives.

That 12 month gap is what gets me. Most malware authors code for quick payouts, they want their stuff running while it's hot, not waiting around like some digital time bomb. But I've seen this exact trick before with older stuff that uses scheduled tasks or registry run keys that survive reboots, they just sit there patient as a spider until the machine powers up again. The cracked game angle makes total sense too, those repack installers from random forums were notorious for bundling miners that would pause themselves if they detected any monitoring tools or if the system went idle for too long. You probably had it running quiet for months before you even noticed, just throttling your CPU whenever you weren't actively clicking around. Good call on the full wipe though, some of those scripts would reinstall themselves from a hidden recovery partition if you only did a factory reset.