ASRock Z77 Extreme6 Random Shutdown/lights on board not working

Hello,
I recently purchased a new Antec DF-85 case alone with a ASRock Z77 Extreme6 from newegg. When i got the board, i hooked everything up with the case, and when i pressed the power button, nothing happened. I went to go read the manual to see if there was anything obvious i was missing, and after 5 minutes it randomly started on its own. It stayed on until the next day and it shut off again. When I start the computer up, 1 of 4 things will happen. Nothing will happen, the computer will turn on and shut off while windows is starting, the computer will shut off after 5 minutes, or the computer will stay on from 1-3 days. If the computer wont start, the best way to make it start is to turn off the PSU for 30 minutes-1 hour, turn it back on, and press the power button. The power button on the board doesn't light up and neither does Dr. Debug. The only signal that there is power to the board is when i have the PSU turned on, the lights next to the Ethernet port are on(even when the computer wont start). I tried pulling everything besides the CPU from the board and nothing happened. Also one other thing to note is that the CPU fan spins at 100% (around 4500rpm) until I turn it down to 70%(around 2100rpm) with speedfan. This is what i have in my computer:
GPU: Nvidia GeForce GTX 570
RAM: 16GB DDR3 Corsair Vencence
PSU: Corsair HX750
CPU: Intel i5 2400k
HDD: 1TB 7400rpm
I was told by a friend that its most likely the board and that i should return it and get a new one, but I was thinking it could be the PSU. I'm somewhat new to building computers and things like that, so i didn't do any fancy overclocking or anything. Any help would be appreciated.
Thanks