I have an iBook G4 1.42 Ghz which is running 10.4 and I have the install disk that came with it which is of version 10.4.2. This laptop broke so i recently aquired an iMac G4 which is running 10.2.8. I was hoping to upgrade the iMac to 10.4 but when i put the grey mac os install disk in and reboot, it starts up the installation screen but before it gets anywhere it tells me that 'this software cannot be installed on this machine.' I am certain that this machine CAN run 10.4, probably even 10.5. Is it just because it's the disk that came with the iBook? and it will only work with an iBook? Will I need a proper retail disk? or is there something I'm doing wrong or someway of getting around whatever checks it is doing?