The basics of my story are in this post:
Please especially see the screen cap pics at the bottom of the post thread.
This seems to be quite normal for a Dell supplied NEC drive in a Dell PC.
Dell support claims that they sent me a nd6500A unit, but when I examine it using your drive convert utility, it tells me that it is a nd6650 (please see attached pic). The drive continues to be able to read purchased dvd movies, and cd data disks as well as movie disks. The only hang up seems to be with data dvds.
Regardless what Dell told you, they definitely sent you a 6650. I wouldn't complain about it
(1) edited the registry (lower and upper filters deleted)
(2) installed new bios
(3) installed new intel chipset
(4) unchecked DLA
(5) enabled recording
(6) reinstalled power dvd and Sonic
(7) changed boot sequence to cd/dvd drive followed by HDD
(8) countless other things that I cannot remember!
but they have been unable to help.
(9) Install a clean Windows from scratch without any additional software and see if you can read data DVDs this way.
If you cannot install a new Windows, you might try something like Bart-PE or Knoppix. Did you already try a bootable DVD at all and see if that one works?