I've answered this type of problem before
1) On the computer ( I KNOW you can't see the screen) press the Windows and P button.
2) Press the DOWN arrow 3 times (for external monitor or just press ENTER for the internal monitor)
3) press enter (if you want the external monitor).
Hey like magic your video will appear on the screen again (Internal screen)
What you are doing is activating this (screenshot enc). Actually can't find the image but look at my post in this thread for the screenshot
( I KNOW you don't have a screen but this mechanism WORKS!!!!). Help Logging In broken monitor
I'm actually on Windows 8 at the moment but it's the same on Windows 7.