Sad news, Nathan. I hope there are some chances left to fix your current hardware.
Maybe you have got some fellow electronics guy around who can look for the cooling system again and maybe test some things to find a culprit.
I doubt that the whole system is lost but as laptops are one dense packed accumulation of things that work at higher idle temps to avoid big cooling devices, one thing seems to breaks the chain here.

A had some desktop systems going to heavens bit by bit and one usually starts to first find: the faulty device and second: replace or disable it to keep the rest running.
So maybe "just" e. g. the USB controller, the one for the disks or some other chip is ending his life now and currently triggers the rest to go with him.

You plan b task now is to take part in every lottery of this planet where they at least offer some new laptops.  :D