Cannot switch back to LCD display.

I recently brought my laptop into class for a presentation, a fellow student setup the external projector for me. Everything went fine. But I shutdown my computer with it still using the external display. When I got home I can see the screen with the Windows bootup but once I get to the login part the screen goes black. I've tried the Fn+F7(display switch for the laptop) and nothing is working.

Is there anything I can do without using an external monitor?