A couple of weeks ago my 2011 MacBook Pro died. Well, not quite died, but the video stopped working which amounts to the same thing. Both the screen and external monitors exhibited severe monochromatic lines and ghosting of said lines. It wasn't pretty. It wasn't even art. It was infuriating as it was outside of the AppleCare warranty, plus this had happened once before and had been repaired.
Apple
There are several methods floating around the Interwebthingy, but this is the method that worked first time for me after several other methods failed miserably.