Hello, as best as I can tell, I'm having the same trouble with both internal drive, and now external added drive, both not working. Based on the various comments, I'll first try to provide you my machine details.
iMac (12-18 months old, bought new)
2.5 GHz Intel Core I5
4GB 1333 MHz DDR3
OS X version 10.7.5 (11G63)
Graphics AMD Radeon HD 6750M 512 M
what models the DVD drives are
The internal "superdrive" is HL-DT-ST DVDRW GA32N, firmware KE06, ATAPI.
The external (I think) is HL-DT-ST DVDRAM GT80N (it's a brand new Amazon Basics USB 2.0 External Slim DVD Writer). I actually got two new ones (shipping error), but neither one works).
buss or self-powered and like your asking running thru a buss or self-powered USB Hub? Sorry, not sure what this means?
I don't use the drive very much at all, but it worked fine the last time I did. The other day I tried inserting a new music CD and got nothing, repeatedly. After reading around online, I got the Amazon external drive, but again nothing. I tried the Amazon drive on a small HP notebook I have and it worked fine right away. I don't know what else to do, but the postings here sounded hopeful.
The SMC and PRAM reset mentioned in the original replies has not worked. Nothing has so far, and no music CD or movie DVD (both new, very clean). The only way I am able to eject the disks (internal or external) is via Disk Utility.
I "think" the disks must be seen by the computer/drives somehow, because I'm ultimately able to eject them from Disk Utility?? Also, I inserted a Harry Potter movie disk, and the name of the movie was actually shown in the Disk Utility screen. But nothing played, and iTunes has never opened in any of my disk insertions (and I know it is set to open automatically when disks are inserted).
I don't know what else to offer, but if you have any questions I'll be happy to provide what I can. I look forward to your assistance!! Thank you,
Jeff