Unresponsive when turning off one monitor in duplicate configuration

I've installed win8 on an xtreemer ultra media center. It's connected to a projector and a touch screen monitor in duplicate screen mode.
Sometimes I would like to keep projector off and only use monitor.
Problem is when I turn off the projector. You hear the sound that windows detects a disconnected device. The image changes to a clean desktop (used to be lock screen, but I disabled that). And system becomes unresponsive. No cursor can be found. No metro interface. Microsoft+p is not displaying.
Tried everything I can think of.

Any ideas?

Not an answer, but I was looking for the solution to a similar problem. I have my TV as my main monitor screen. If I switch back to the TV source and then back to the monitor I get the same problem as above.

Grace