If its repeatedly resetting itself; as if attempting to post but then cycles back thru a reboot.... pop out the quarter sized battery on the motherboard.... keep it out for about a minute.. pop it back in. Of course, I would do this with no power connected to your pc. This will reset your BIOS as well, so if you've made any changes from the factory setting, you will need to enter your BIOS screen and make the changes again.