I've owned this motherboard since August or so in 2013, and has worked fine. However recently my PC decides to shut down and start up in a loop which I can't stop unless I unplug the power supply. After trouble shooting I thought it was the PSU, bought a new one and it still does this.

I have, however made a little head way. If I unplug the main motherboard power supply and plug it back in, I ca get to the BIOS settings, however it does not see my HDD at all. Can anyone give me a hand with this?

My rig is as follows:

i7 4770k
Corsair CX750M (new)
Geforce GTX 460
4GB RAM x2