My 4600C had its first and only thermal shutdown yesterday. Since the event, the computer boots and operates, but the cooling fan runs full speed all the time, regardless of the CPU load. To address the issue I have cleaned all the heat sinks, and re-potted them with new thermal compound, verified that both fans in the unit are turning and moving air, and updated the BIOS. None of this has solved the problem. It’s as if the event has set a code somewhere in the machine which commands the fan to run full speed. Any ideas on how I might solve the problem? P.S. The Dell tech chat says the fan needs to be replaced; but this makes no sense to me.