Auto-Restart Mystery Problem

Problem:
My computer fails to go into Sleep mode, and it also will automatically restart about 1-2 seconds after shutting down.

This issue initially arose when I had the RC installed. During that time, I had been able to Sleep the computer just fine, but one time it seemed to randomly fail. The screen merely went black (the monitor was on, but it was displaying a full black screen) and the computer itself still seemed to be fully on. No keyboard or mouse input would put me back in Windows, it was just stuck there, so I powered it off. After that, booting up failed (a couple times) because it was trying to resume a failed sleep state. Once I got it to boot normally (by selecting the "delete restoration data" option), sleeping would still fail and shutting down caused an auto-restart. I now have to shut down, wait for the computer to automatically start booting again and then hold the power button to get it to turn off.

Attempted Troubleshooting:
Since then, I have flashed my BIOS, reset my BIOS to defaults (multiple times), and done a clean install of 7 Professional. I had thought that since flashing/resetting my BIOS didn't fix anything it was a problem with my Windows install, but since the problem has carried over to a clean install of the OS I'm now inclined to suspect the motherboard or BIOS again.

I have made sure that my LAN cards (wired/wireless) are both set to not wake on LAN activity. All of the special "Power On" settings (keyboard, mouse, etc.) in my BIOS are disabled. All of my drivers are up to date, and I'm sure that I have no malware/viruses infecting my PC. I've also tried closing all programs and turning off my monitor before shutting down. Nothing has worked.

The only thing I can think is that some small part of my motherboard is corrupted or damaged, though everything else seems to be functioning just fine. Does anyone have any idea what's going on?

C:\Windows\Minidump

Use Winrar to make a .rar of the latest 5 or so .dmp and upload to Rapdishare.com, post a link here.

That folder doesn't seem to exist on my install.

Go into the Control Panel... Goto System & Security...Click on System. Click Advanced System Settings...Under Startup & Recovery, click Settings...Ensure the checkmark is removed from Automatically Restart...Then Ensure the drop down menu says "Kernel Memory Dump" and that the Dump File is :

%SystemRoot%\MEMORY.DMP

Which would then put any files in C:\Windows\Minidump OR where ever you installed windows (a different drive letter, or file path if you renamed the Windows install directory... for example : D:\Win7\ or D:\Windows\ )

Those things were already set as such. I haven't shut down in a long while, and I did Disk Cleanup fairly recently. Maybe it removed those files. Would shutting down or sleeping possibly create a new one? I would think it would only happen if I tried to sleep it, because shutting down doesn't really seem to be causing an actual error, just a strange restart.