Thanks anyway Mayer...You're advice, though eloquently written as it was, did not fix my problem..... It turned out that I DID NOT reconnect the optic drive connector board nicely at all to the logic board. A big part of my problem was dealing with those blasted "Ears" that hold the optic drive down to the inner frame of the iMac. That snap-together fastening system is a hassle! This is an Apple computer, not a Revell plastic model! Anyway, my optic drive works again.