It's some kind of internal issue. I've tried two different AC adapters that work and nothing. I know the computer is getting power from the adapter because it actually turns on (I can hear it and the CAPS LOCK key lights up). However, I don't get the chime or anything. It's not the HD cuz it doesn't have the blinking question mark it's just a black screen. I tried increasing the brightness but nothing.

Click to expand...

The dead Duo that I have is a bit like this - the caps lock key lights up but there is no sound, no chime, no life from the screen - I thought at first it must be a power issue, but hooking up an external screen and floppy drive showed that the machine is actually working, just someone's had the hard drive out of it and the screen must be dead. So I would try an external screen to see if your PB's screen (or the connection to it) is dead; however looking at my 520 it seems as though the display connector is a very weird one, so you may well not have the correct adapter for it.