Random PC Restarts

For the last month or two, my PC has been randomly rebooting when I played Skyrim, while I attributed it to a lot of the mods at the time, it's now crashing when just on the desktop just after boot... In fact it crashed before I started to write this post. I'm stumped. Nothing is overclocked, and all the components besides the RAM and PSU were replaced mid last year.

I'm guessing it's my power supply. I checked the hardware monitor in the BIOS and it showed about 2.89v on the 3.3v line, about 6v on the 5v line, and 13.98v on the 12v line. I don't know if that actually means anything, but I've never seen numbers like that before. Can you guys help me confirm/deny this...? I would love to be wrong, because I really cant afford a new PSU right now, but I've eliminated every other option. I have no multimeter, but maybe could take it to the local PC shop if that could really help troubleshoot.

Here are the specs:
ASUS P6X58D Premium Mobo
Intel i7 960 3.2Ghz w/ the Noctua DH-14 i think
AMD HD7970
3x2GB Corsair Dominator GT @@ 1066Mhz
2x1TB WD HDD's in RAID0
on a 850W corsair PSU

Is that too much for my PSU anyway? Like I said not overclocking, but I am running a TON of stuff off of USB.

edit: might add that I just plugged my PC into the wall out of the powerstrip and it still is happening.
Furmark is also rebooting it now too, just tried. What leads me to suspect the PSU even more is that I hear the PSU fan turning all the way off before turning back on again..