Running Windows 7 Ultimate. I wanted to connect my laptop to an external monitor so I pressed "Windows key + X", then clicked "connect display", then "extend." On most computers, doing this will allow you to output the display to another monitor. When I did it on my laptop, the screen started flickering and became garbled. It's too garbled to see, and I can't find the mouse and undo what I've done. I tried restarting but it's still like this. Please help! Thank you.