Windows 7 tower won't shutdown correctly.

[Aliastral]

My desktop is running Windows 7 Ultimate (x64).

Well. It doesn't seem to be able to turn off.
If I put it into standby, the computer seems to enter standby state normally, but then a few seconds after the computer starts sleeping the fans start spinning again as well as the PSU's LEDs.

In this state, the monitors both show 'No input', and the keyboard's Num Lock LED lights up whenever I press anything.
The computer is otherwise completely unresponsive to input.

The only apparent way out of this is to hold the power button until it fully shuts down.
Turning it back on makes the computer go through the BIOS, POST, etc., before Windows tells me that it is resuming.

It proceeds to resume, showing a black screen for an abnormal amount of time before finally returning me to the desktop.

I'm not sure where the root of the problem is, and I'm not sure where to start looking.
Sorry for the wall of text, and thanks in advance.

---

Windows' error logs report that the system goes into sleep without problems.
Specifications are as follows:
MTB: Asus P5QL-PRO
PSU: 500W
CPU: Intel Core 2 Quad Q8200 @ 2.33GHz
RAM: 8GB Kingston DDR2-800
GPU: nVidia GeForce 9800GTX+
HD1: Western Digital Caviar Green 500GB SATA
HD2: Western Digital MyBook 'Essential' 640GB USB


All the best,
~Aliastral

 

[gravator]

Make sure your HD is not turning off after a few min under power options.

 

[Aliastral]

Thanks, trying that.

All the best,
~Aliastral

 

[WinGeek]

If the problem still persists, create a .batch file and check if there is some problem with your drivers.
Or some times its is the antivirus causing that trouble. Have you installed ant antivirus in your system. Try replacing it with another one

 

[Aliastral]

My installed antivirus is Norton Internet Security 2010, 17.5.0.127.
Could you clarify what you mean by creating a .batch file?

Thanks,
~Aliastral

 

[gravator]

Any thing look better?