Icon from the Tango Desktop project

When I turned on my first generation Core Duo MacBook Pro I got in early 2006 this evening the backlight refuses to turn on using the function keys on the keyboard. All other keyboard functions are fine.

If I shine a torch at the screen I can just barely make out the windows and can adjust the brightness slider in the Display prefpanel, but nothing happens. Using an external monitor I can use the machine, but the internal display is still black.

Not sure whether this is a problem with Snow Leopard, I sure as heck hope so but it's looking increasingly unlikely. I didn't have the backlight Snow Leopard installation problem, but could this be related?

Things I've tried so far and have failed:

  1. Resetting the PRAM (three times)
  2. Resetting the PMU

This is really serious. I need to take this machine to classes. If it's a hardware failure and I can only use an external display, I'm in big trouble.