Hi, I've found a buyer for my old PowerBook 12" G4. The hard drive has been erased, and it won't allow a new OS to be installed. I've tried: 10.2 (gray disk) - weird ascii error 10.3 (3 black disks) - cannot install 10.5 (gray disk) - too new. I can't find 10.4 - which is what was on the G4 before I erased it. Any advice?