Believe it or not, this could simply be a firmware update.
My relatively new multi-format (CDRW/DVDRW/DL/lightscribe) drive would occasionally not recognize disks in the drive. When I searched the net I found lots of people had similar problems.
Further searching at the manufacturer turned up firmware updates, which so far (knock on wood) seem to have cleared up the problem.
If you find firmware updates for your drive, I recommend you reboot to a clean boot before applying them.
I think the manufacturers are rushing the products out the doors and letting us do the final testing on them.