I am trying to wipe and reinstall 10.5.6 on a drive on a Mac Pro. The disks that came with it originally (original 2.0 Ghz Dual Core Intel) were a two disk set that installed 10.4.10. It also came with a drop in disk to upgrade to 10.5.6. I am almost positive that the upgrade disk is what came with the machine, but maybe I am wrong! Problem is when I wipe the drive and install 10.4.10, and then try to upgrade it to 10.5.6, the upgrade disk just pops out of the drive. It mounts and when I hit restart to start the install process, it pops out. I checked the disk with disk utility and it checks out fine. I also have a full 10.5.6 Install disk which also mounts, however during the verification phase it claims that there is an error on the disk. So currently I am SOL. Anyone have any ideas. Thanks.