Is anyone else experiencing this issue? I have a external monitor plugged in and I use my Macbook Pro (2009 Uni) as a secondary monitor. Randomly, the macbook screen just goes black. If I move my mouse on to the macbook screen, I can see the mouse cursor, but the rest of the screen is black! It's driving me mad! The only fix is to un-plug the monitor adaptor or adjust display arrangements. It's really cramping my style.