My monitor won't stay off when in power saving mode?

Hi,

I have been battling this problem for a while. I use XBMC media centre to play TV & movies through my pc. I'd like the monitor to turn off after an idle period. XBMC has a feature built in to turn the monitor off.

However when the monitor does go off it always comes back on a couple of seconds afterwards, flooding my bedroom with light.

I have tried writing a small batch script to turn the monitor off that i can control from my remote control. The problem still happens.

I have a laser mouse that i thought was the problem. However the issue still occurs when the usb cable for the mouse was unplugged. I have also tried turning off both of my external hard drives & all other usb devices.

The problem still occurs when XBMC is closed & I am on my desktop. I have closed all other software bar my AV & firewall.

What else could cause the pc to come out of idle mode. I'm stuck on what to try next. Any suggestions? I'm using Windows 7.

Thanks

 

I've tried all of the following to no avail...

Disabled Wake on LAN in bios & in Device manager.
Disabled software being able to wake.
Stopped all devices (except the keyboard) including the mouse from being able to wake the computer.

It's a very odd problem. :/