powerbook g4 problem reading snow leopard dvd

I am and it tech at a uk university, and should really be able to come up with an answer but i am struggling with this one.

I have a powerbook g4 running os 10.4 that i want to upgrade to 10.5 to se time machine. I have checked and according to apple i should be able to run 10.5.

The problem is with the mac reading the install cd. When i restart holding c it doesn't read the cd and spits it out. When i start os, it also doesn't read the dvd and spits it out.

I have checked other dvds in the drive and it reads them. I have checked the 10.5 dvd in another g4 powerbook of the same spec and model and it works fine.

I have tried it in an external usb dvd drive on the mac and it will read the dvd in os, but not on startup, i thin because usb is loaded after os starts.

The dvd is the black one not the grey one if it makes any difference

anyone know of a way i can install 10.5 on this mac? or why it will not read the dvd?

cheers

Try booting the G4 with the disk in and holding "alt" key just after the startup bong and see if it lets you select the dvd then.

- Simon

nope just tried it, spits dvd out without reading it. Its the strangest problem, all other dvds work except leopard installation disks. i have two different disks and neither work.

Just to clear something up here>
Is it Leopard 10.5 or Snow Leopard as your header suggests?

yeah sorry i just noticed the mistake. i am trying to upgrade from 10.4 to 10.5, i realize 10.6 would not work as it needs an intel processor..

Ok that cleared up, I had a similar problem, my G4 just would not install from the disc, no matter what, and the only way I could get it to work, was to partition the HD, create a .dmg image of the Leopard disc, and put it on a small partition, and install from there. It works fine, but is not ideal of course.
If it's something you want to try I did post full details of my work around at the time, I will try and find it, but it was ages ago and I post a lot!