I have a Asus laptop with Windows 7 on it. And when I plugged in an external vga-monitor I wanted to extend the desktop between laptop monitor and the external one.
After pressing Windows+P a few times. The picture went away from the laptop monitor, never showed up on the external monitor. And now I can't get the picture back when the vga-cable is plugged in. If I unplug the cable. The picture shows up on the laptop monitor.
The monitor and cable is working fine with another computer. so I'm pretty sure that the problem is with the laptop.