My computer's newest habit is rebooting without an error almost every time Windows starts. It gets to the desktop, starts loading all the programs, and lets me do stuff, but reboots before everything is done loading. Windows safe mode is unaffected. I ran MemTest86+, but it found no RAM errors at all. Reboots at times other than booting are very rare, but it happened once yesterday. I don't know if this is software or hardware related; I find it hard to believe it'd be a SATA/RAID problem, considering the frequency of reboots now compared to before (every system boot versus almost never after installing the 790i SATA/RAID drivers). I unplugged my SATA optical drive to ensure it wasn't at fault, but it didn't help at all. I tried changing my CPU clock speed back to stock, but that had no effect, and I've been able to do CPU-intensive things without reboots (hours of Bioshock and a Half Life 2 mod).

I'm baffled and have no idea how to narrow this down. It's to the point where I'm tempted to start RMAing random parts until the reboots stop, but that's something I really don't want to do. Is there any way to force an error rather than automatically restarting? I set Windows to not automatically restart, but it's doing so, anyway. I'm not sure at all what tests to run, settings to mess with, etc. I'd guess this is probably dying hardware, and I'm inclined to think it's the P7N simply because it doesn't seem like it would be anything else now after getting no errors in MemTest86+, but I really don't know.