Windows 7 restarts, or attempts to, randomly(64Bit)

This has been annoying me for quite some time. Windows 7 restarts itself randomly. And I don't mean that something errors, I get a BSOD, and the computer restarts; Windows is actually just trying to restart itself. Sometimes it does this while im using it, but mos tof the time it happens when the computer is idle for a while.
This made me think that it was an issue with power managemnt, so I changed my power plan to High Performance Mode and then went into advanced and changed everything so that NOTHING would turn off no matter how long my computer is on.

The restarts continue to happen.

To make sure I wasn't getting BSODs, I changed some setting (read a tutorial on these forums from someone who was having a similar problem) that makes it so if I get a BSOD, there is no automatic restart. Since then, I have had multiple restart occurrences with no BSODs and no error messages when the computer starts back up.
Another way that I know it isn't erroring is that Windows attempts to shut down my processes when it restarts but does not force them to close; as in I come home from school to a message from FRAPS saying "Are you sure you want to close? If you exit, your frames per second will no longer be displayed." (or something to that extent) and if I hit cancel, the restart operation is stopped and I can continue using the computer.

I also checked Windows Update, but I had a restart problem today and the most recent updates were applied like 4 days ago.

I have no idea why this is happening. There are no errors, and even as such, I've made sure that all of my drivers are up to date.

Any help would be greatly appreciated, thanks :)

Feel the top of your case - is it warm or hot?

Feel the air blowing out of the power supply - is it there at all? Is it warm or hot?

Vacuum out your PC. Point a large house fan at your open case and run it that way. Does the problem recur?

I don't think it's a problem with my system overheating. My PSU does run pretty hot and I do have an overclocked processor, but I clean my case out regularly and my CPU rarely goes over 50c (Usually around 40c). I also recently upgraded the 120mm fans in my case to fans that move 90cfm which keeps things quite a bit cooler.

Random computer restart without BSOD or overheat indicates PSU or CPU fault.

It could also be that the electricity in your house is not stable, so whenever the voltage dips, the computer restarts itself. Do you have an UPS or an AVR (active voltage regulator) device?

Hmm... the only reason why I don't think my parts are bad is that they're all quite new and I NEVER had these restarts on XP. I am running the same OC settings and everything that I had stable for months on XP and it runs fine on 7 even when maxing out the load... just random restarts

and @icoola77 I actually have a UPS (APC Back-UPS R1500) that is only being utilized to about 1/3rd of its capacity and I am using APC PowerChute Personal to allow it to talk to my computer. I looked at the history of shutdowns or errors in it and the last 4 weeks I've had a total of 9 blackouts and the computer has only run on the battery for a total of 59 seconds (The power flashes a lot here which is why I bought the UPS )

If I understand correctly, you're experiencing an unwanted but "graceful" shutdown?

As Antman said, spontaneous reboots are frequently linked to unreliable hardware, but if your OS is actually going through the shutdown sequence first - even though you didn't initiate it - then the suspicion shifts back to software.

If you check your system and application event logs in the few minutes just before and just after the "mysterious shutdown" event (run EVENTVWR), can you see anything at all that looks linked to the start of a shutdown sequence?

Sometimes these issues are caused by malware. Sometimes it's dying critical processes. And sometimes your mates are playing a joke on you.

Good catch, acidic one. I simply assumed an other than graceful shutdown.

How did I miss-

"Another way that I know it isn't erroring is that Windows attempts to shut down my processes when it restarts but does not force them to close; as in I come home from school to a message from FRAPS saying "Are you sure you want to close? If you exit, your frames per second will no longer be displayed." (or something to that extent) and if I hit cancel, the restart operation is stopped and I can continue using the computer..."

How? Gracefully, of course.

Antman said:

Good catch, acidic one. I simply assumed an other than graceful shutdown.

How did I miss-

"Another way that I know it isn't erroring is that Windows attempts to shut down my processes when it restarts but does not force them to close; as in I come home from school to a message from FRAPS saying "Are you sure you want to close? If you exit, your frames per second will no longer be displayed." (or something to that extent) and if I hit cancel, the restart operation is stopped and I can continue using the computer..."

How? Gracefully, of course.

Yeah, I was half-way through writing a "please clarify" response when I concluded the OP did in fact describe an unwanted graceful shutdown/restart. It's not particularly clear and terminology is always an issue in this context.