OMGIllithan said:
Turns out it was my power supply. I did a few of those tests on the page without finding anything, when a friend on mine suggested it might be my power supply. I swapped in his just to test it and I booted up fine. I guess it makes the most sense out of anything but it makes me sad to think I've only had that power supply for just under 2 years....
Glad you found the problem. Thanks for letting us know.