I have an old G4 Gigabit Ethernet, 512 Kb Ram, 10.4.7 that has lost the ability to recognize DVDs. I have tried 3 different internal DVD drives, tried switching the jumpers around in each, reset PRAM and firmware, reinstalled the OS, tried 3 different internal cables and several different media, and those media (burned and not burned) work in another Mac. The DVD drives do work in another Mac that I have. The DVD drives are recognized under system profile under the ATA and Disc Burning sections as DVD burners. The drives all also recognize CDs and can burn CDs in this Mac, just cannot recognize DVDs. Any ideas before I go out and buy fresh cables and another DVD drive. Thank you.