A friend of mine's PowerBook has a problem - the backlight won't work, so essentially his screen cannot be seen. If he shines a torch onto the screen, he can see the desktop, so it leads me to believe that the machine is fine other than the backlight.

Any idea of this is a software problem that can be easily fixed, or has the backlight blown?

Either the backlight has blown, or one of the very small and delicate cables which run through the hinges (and either a)power the backlight or b)tell the backlight when the screen is closed) has broken. Will it work if you try gently moving the screen to different angles? Or does it simply not work at all?

The backlighting consists of a long thin cold cathode tube that does just that, illuminate the screen at the back Was the display flickering before this problem arose?

Unfortunately it's not a cheap fix requiring replacement of either the screen's inverter or the entire screen itself. What model PB?

JB

same thing happened to my PowerBook a few days after I got it James!! It was the inverter - when the PB was plugged into an external display, it was all fine. Under warranty it took two weeks and zero dollars to replace. Hopefully your friend's PB is still under warranty!!