First power up: turns on and off

Hey! So I built my new rig and when I turned it on, it came on. After a few seconds, it turned itself off. Then it came back on, then off, on, off, etc. When it turns on, the PSU makes a click, and when it goes off it makes a click. Does anyone have any idea as to how to fix this? I've tried taking out either stick of RAM and turning it on, that didn't work. I reseated the mobo pwr connections and that didn't work. There is no voltage switch on my PSU as it's supposed to change by itself.

Thanks!
--Hayden