If you have used the FN+F8 keys to toggle between screens, re-hooked the projector, and have restarted your computer, then you want to take it in to a local computer tech to diagnose the screen display issue. If you are in the need for a laptop, take a look at some of the laptops we offer at AA Rental.
Laptop Rental- http://aarental.com/laptop-rental/
Ben
Lead AV Tech, AA Rental