So when you say you reinstalled all components, does that mean that you reinstalled the OS? Do what Mailpup said and check in the BIOS, and I know this is trivial, but make sure there is nothing wrong with the fans on the CPU cooler, often times some motherboards won't report a CPU fan failure or absence, simply because they are often just left out of the loop and replaced with a different fan controller. Mine is, at least. Also, see if your CPU is officially compatible with your board. If it is, you should upgrade the BIOS, if you upgraded to a different generation CPU then it might need an update.