I just replaced the HDD in my 1.8 G5 iMac and tried to install 10.4. It gave me an "Alert! You cannot install this software on this computer" message. The install disks are printed: iMac G5 Mac OS X Install Disc (1/2) Mac OS version 10.4 Disc version 1.0 2Z691-5317-A so I figured these would work (picked them up on eBay -- I know -- caveat emptor). Are these disks really incompatible? I intend to transfer over the entire contents of my G4 iBook -- I just need to get the iMac up and running. Any ideas? Thanks.