Re-opening this because the original problem still exists (fully updated Natty beta as of 6 April). If I boot with external monitor attached, the screen of laptop and monitor turn black as soon as I log in. If I boot without external monitor, I can log in and the desktop appears as expected. If I plug an external monitor or projector in after the desktop is running, then it either turns black or a blinking solid dark red colour.
Re-opening this because the original problem still exists (fully updated Natty beta as of 6 April). If I boot with external monitor attached, the screen of laptop and monitor turn black as soon as I log in. If I boot without external monitor, I can log in and the desktop appears as expected. If I plug an external monitor or projector in after the desktop is running, then it either turns black or a blinking solid dark red colour.