The assumption is still that it is a temperature issue. Based on the readings so fasr, I would not expect a commanded shutdown.
GT, have you checked through the error logs as found in the event viewer? This really should be your first port of call, since windows logs everything it does in there & it will be a mine of information for you. Everest will tell you what temperature the machine is operating at, the event log will tell you when it shut itself down & in all likelihood, why.