Hi, I recently bought an installation disk off eBay. I have tried and tried to install on my PowerBook G4 but nothing works. I have been on loads of guides and formatted the hard drive etc. But nothing works. It just says Mac os x cannot be installed on this computer.. If I put the disk into a newer mac the read me file says it works for Intel and PPC macs. And the disk doesn't appear to be any specific mac as it just says something like Mac installation disk on the front. I just don't know what to do, can anyone help??