I have an ASUS Netbook MT101 (touchscreen) running Win 7 ultimate on an Atom 450 proccessor. I hit the Win + P to switch to an external monitor. That worked fine. Then I went back to settings to take off the monitor and got back to just the notebook screen. That also worked fine and my external monitor goes off.
Now here's the problem. When I got to disconnect the VGA cable, the screen on my laptop goes blank. Plug back the VGA cable (even if monitor is powered off) then the screen immediately goes back on the laptop.
I tried the Win Mobility Center, I right clicked on the desktop to acccess the Intel graphic properties and options. All of which show my laptop and the primary and selected screen.
I unplug the VGA cable and it goes off. Plug it back in and the screen on the laptop comes back on.
One more thing, the toggle function between laptop and external monitor does not seem to be working. And though I have hooked up my laptop prior to other projectors, this was the first time I got it to work on an external monitor. Prior attempts failed. Seemed again that the toggle switch wasn't working then either.