Computer turned itself off, fans spin and stay on but no boot seqence

[xCluck]

My computer completely turned off when I was playing a a game, and turned back on immediately without entering the boot sequence (distinctive beep signals that). When I turn it off and turn it back on, all the fans spin up, but still doesn't enter the boot sequence. It stays in this state until i turn it off again. This happened a couple nights ago as well, and I left it off overnight and it turned back on in the morning and booted properly. So i thought it was a one time thing. Whats going on? Most problems ive searched like this the computer power cycles or the fans only stay on for a second.

Asus Sabertooth z77 mobo
i7 3770
Zotac gtx 970
8gb corsair vengeance ddr3 ram
cx500 psu

 

[FacePush]

Do you have another power supply that you can test the system with? Also something to think about if the CPU is getting too hot it could be putting itself into safe mode, essentially protecting itself from being fried but not letting you preform any functions until it cools off.