I got a couple of PowerBook G4 from Uni and I'm trying to re-install Tiger onto it. I got it to start loading from the CD but as soon as the screen turns blue (the background colour for teh first screen after booting from CD) the whole laptop locks up. Not even the mouse moves. This happens on two PowerBook G4 i got with me. So now I'm wondering is there some way of locking it up from loading off a CD? If so, how do I turn it off?