Im using an iMac G5 (isight) 17" and it's not reading my memorex DVD+Rs, WHICH I ALREADY HAVE USED IN THE PAST (same package of dvds). it simply isn't acknowledging that it is in the computer, so it's not spitting it back out like it did with incompatible DVDs i've had in the past. i repaired permissions and reset PRAM. and restarted. still no go.