Machine doesn't power off when "Shut down" via Windows

Stovepipes

Honorable
Jul 29, 2013
2
0
10,510
I recently built my first machine (and I'm loving it to death), but I've been having one minor issue with it. When I try to shut down the computer via Windows, the machine itself stays on (fans still running, I can open the disk drive, etc.). I've been shutting down the machine by holding down the power button, which always works just fine. The computer CAN restart fine when selected via Windows, and it briefly shuts off while doing so. I have the latest drivers installed for my mobo and graphics card. Any possible solutions?

Specs:
ASRock H77 Pro/MVP Mobo
NZXT Tempest 410 Case
Intel i5 3570 @ 3.4 Ghz
Corsair CX500M PSU (500 watts)
 

Stovepipes

Honorable
Jul 29, 2013
2
0
10,510
I've swapped the PSU and found that it's not an issue with the power supply. I don't suspect that it's an issue with the motherboard either, as I CAN turn the machine off by holding down the power button, just not through Windows.