You might have a bad CPU. I just upgraded my main HTPC to an i3-2100t and the first chip I received was bad. One thing strange was that the CPU worked for the first install, then a couple of days later failed to boot. I thought maybe corruption issue or driver issue, so attempted to re-install then discovered that Windows install media wouldn’t boot. Of course, I had to rebuild the system several times, using different motherboard, different power supply, different RAM, etc, before it boiled down to a bad chip.
