I am fairly ignorant about computers, so bear with me. But please try to help! The SuperDrive in our 2-year-old iMac conked out and we desperately need to burn a DVD. I borrowed a Plextor burner from work, hooked it up via FireWire. But how do I make the computer recognize this external Plextor burner? When we go to iDVD and try to burn, it obviously spits out the tray and asks us to insert a disk. We want it to use the Plextor. Any kind souls out there know how we can bypass the iMac's SuperDrive?