I just had this very same realtime error. As Bob R. said, I removed the heatsink and discarded the aluminum spacer (and white dust that used to be thermal paste), reapplied good thermal paste and reinstalled.
I went this way because I've replaced motherboard batteries recently (being very careful to keep power on the board at all times to avoid loosing BIOS). My machine is also converted to SSD and has an ethernet card.
Anyway... it seems to be working again! Which makes sense because it's been quite hot with very little trade winds (Hawaii).
We are adding a small fan right now to further assist cooling. The fan is a Noctua NF-A4X20 PWM and we just wired up a 12v brick to it.
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