Ok, so I've searched everywhere for an answer, but here's the problem. I turn on my laptop and it starts up and shows the grey screen with the white apple in the middle. When its done with that and it goes to the screen to tell you whats loading the backlight goes off. You have to press the Brightness button when it finally gets to the Login screen to turn on. And when you put it to sleep, you can not turn the light back on. I'm installing OS 10.2.0 again to see if this helps, but it probably won't. I've reset the PRAM and PMU x number of times, I've taken out the battery (not the PRAM battery) and that still doesn't work. Does anyone know of something else I could try? Oh and BTW I went into single user mode and tried to type reset -all and that didn't work. This all started after I installed security updates for OS X 10.2.8. Respond to email please. Its slooksterpsv@hotmail.com

Wish I had the solution, but have exact same problem. I also have had to reinstall 10.2 about five times since originally switching to 10. I'm wondering if the backup battery or pram battery needs to be replaced, also. Sometimes, if I've had the laptop unplugged for a while, it will start up with the flashing floppy icon with question mark, the hd tries to spin up, then spins down and after a while, will just shut off. I don't think it's the hd because it will start up off the my G4's install CD and the hard drive spins and shows up. Then, after I reinstall 10.2, all's well for a while. Except for the no backlight on startup and going to sleep, after which I have to restart to get the backlight on after startup and pressing the brightness button. I also have installed the WirelessDriver for my lucent classic gold wireless card. In the install for it, it says not to let the computer go to sleep otherwise it will not wake up. In the first four 10.2 installs and after installing the WirelessDriver, it went to sleep and wokeup fine. Just this last time is it having problems from sleep. Long-winded, sorry. I'll monitor your thread for a solution and I may copy both our posts to other forums and will send something to you if I get a solution.