Completely Random Power Downs + Restarts

[Scionix]

Topic pretty much says it all. My computer will just randomly power down then restart at completely random times. Sometimes it won't happen for hours, and, like just now, It happens twice in ten minutes. Any ideas? I'm thinking one of my PSU cables or something is bad, so I might just re-wire everything again (I need to clean up the back anyway....).

FML 🙁

EDIT: Isn't there a way to check some sort of log and see why a computer shut down? I'll look for that as well...

So, update. While I waited on this thread, I figured I'd finally not be lazy and I'd hook up my front USB ports that the HAF has, so after I do that, I now cannot POST. Awesome. No idea how that happened. So far, I've:

Taken the 8800gt's out and tried each of them singly
taken out all sticks of RAM and tried each one by itself
checked RAM seating
made sure my loop wasn't leaking on something
taken out my sound card
un-hooked everything but the Mobo power

What else can I do? I'm hoping to god it isn't the CPU, as

a.) that would make no sense
and b.) It's only 6 months old, and I looked at it and it looks fine. CPU slot looks perfectly healthy as well.

So, I've got a doozy now, and I have no idea how I caused it. What is the bare minimum I have to hook up to get my comp to POST? My 750i is giving me an "FF" which means fully functional, so I don't think it's the mobo either...

KILL ME LSDKJFLSKDJF:SKDJF

 

[Lifixs]

Is your operating system going through the restart procedure or is it just cutting to black?

 

[Eeqmcsq]

I'd suspect the power supply. I had similar out-of-the-blue reboot issues before, which went away when I replaced the power supply.

 

[Scionix]

Can't POST now, FML

EDIT: Lifixs, the whole computer shuts down. The OS doesn't power itself off nicely, the whole rig just goes kaput then restarts itself. But now this is the least of my worries as somehow I cannot POST. UGH UGH UGH UGH