Computer hardlocking after fixing an overheating problem

[rssssssss]

My cpu was overheating pretty badly (getting up to 80 C and hardlocking the system) so I attempted to fix it. I removed the HSF and applied new thermal grease. Reset the HSF plugging it into the CPU_FAN socket where it used to be in the wrong one. Started the computer and it's now running at 45 C. Thought everything was fixed but sure enough the hardlocking was still occurring. It's not happening as often as it was but it seems to be occurring when the cpu is running at 100%. Could my cpu somehow be malfunctioning because of the previous overheating or are cpu's a "works perfectly or doesn't work at all" situation?

If it's not the CPU then what else could be causing it?

[saphalline]

Woah... 80C...

There's a good chance that CPU is a goner. Especially if it's an older one that can't automatically clock down or shut down to save itself. I'm guessing it's an older one since it went up to 80C without stopping.

Hardware specs? OS?