PowerBook Won't Boot From Install CD

Short form: My PowerBook Won't Boot from any Install CD I insert into the disk drive.

About a year ago, I was using my 12" Aluminum PowerBook G4 with Mac OS X Leopard when it froze. I forced it to shut down and when I turned it on again it booted no further than a gray screen. Since then, I've tried every boot-up command I could find, tried re-installing it and as a last resort, wiped the drive and installed Lubuntu Linux on it. I even bought a few Dual-layer DVDs so I could burn an ISO of Leopard onto it. No success. I've tried lots of install CDs including a gray software install disk for an earlier PowerBook. Nothing seems to work except Linux.

I'd really like Mac OS X back on my PowerBook. Any suggestions? Is there anyway to boot from USB?

Any help is appreciated.
Thanks, Seth

🙂