Ive seen a few messages in some threads discussing different versions of panther- upgrade vs retail -and that they each have different numbers on the disks. the panther i got came pre-installed on the new ibook, and its disks had different numbers than both versions earlier discussed. mine said 2z691-4554-a and 4555a- and 4624-a. Is this the same as the retail version, and most important-can i use this software to erase and clean install panther to my other machine- a g4 466 with 10.1.5. also will i have to re install all apps like photoshop dreamweaver, etc after a clean install or can i transfer them over from the hd backup on an external drive? thanks for any help- Im pretty new to working with computers for anything other than itunes & iphoto.