Windows 7 Laptops Randomly Blacking out

I have a weird problem with 30 RM laptop, they have been randomly making the screen go black in lessons. No noticeable pattern, I thought it might be Chipset, AHCI Drivers. Even thought might be dodgy batteries No luck! Event logs were empty!

However I have discovered its something to do with multiple monitors, if you plug in a external monitor the screen returns to normal. I then noticed that the laptop had decide that it had two screens (In additional to the external monitor).

I found by pressing Windows-P and choosing duplicate display the laptops were restored to normal.

Anyone got any ideas why they would randomly be getting this extra monitor! Or a way round as pupils short cut keys are disabled!

The screen can go black for a few seconds if windows 7 is forced to put the desktop in basic mode. maybe you have a program that dosn't like aero. it also goes black if it's trying to show the secure desktop.

also power saving...I'm sure you checked but is it set as a standard for all users via GPO?

My first thought was power, I have set the power to all be the same using powercfg

Aero is disabled and so is UAC, so its not them causing it to go black.

It definitely is a rouge monitor, as soon as you plug in another VGA input it comes back to life.

This morning to try and combat I have added this line C:\Windows\System32\DisplaySwitch.exe /clone which sets it to duplicate, no feedback ye tho

New / older graphics drivers? The intel drivers (soz don't know your gfx card) have their own power management setup now. you could even try fiddling with the graphics acceleration.. still your solution looks like the best.