PowerBook - PowerBook G4 will not boot

My PowerBook G4 starts and I get the screen with the Apple logo and the circular loading animation. It hangs at this part. It will sit there for hours looking like it is booting.

I can insert my restore CD and boot from that only for it to get similarly stuck. It gets to the point where it asks me for the default language for the installation and I click on the next arrow. Then it says "Preparing Installation" with the animated loading bar under it. It sticks there, constantly whirring the cd drive and the animation never freezes. Again, I have let it sit for hours to no avail.

I have tried zapping the pram and nvram but nothing works. Help!