Try the latest BIOS. Be sure to follow the maker's instructions plus one more thing. I find it best to reset the BIOS to be sure it's loaded with good default values.
Last month my PC started to not starting when I pressed the power button, and I switched the power supply on and off and the PC started on its own and quickly shutting down before it could even boot the BIOS.
I sent it to the guy who built twice and the problem vanishes for 2-3 days and suddenly my PC turns on on its own and shuts down i can't turn it on again.
I've done a complete test on the power supply, I tried turning on without RAM , off board video card, Processor. Just with the motherboard on and the fans.
But the problem remains.
What is happening?????
Nvidia Zogis GTX 770 Superclocked 2GB
Motherboard Gigabyte GA-Z77M-D3H socket 1155
2 Kingston RAM sticks of 8GB each
Intel core I7 3770K
Power Supply Seventeam 750w V-force ST-750Z-AF 80 plus bronze