The device manager is where the error message showed up for the DVD player
But, good news! I actually fixed the problem since I posted, so I wanted to let you know what I did. It was the upper and lower registry entries afterall, which I discovered on a whim by going to the Nero website and finding "Trial Version 8" for Nero. I had already deleted the filters in the registry, but there must have been something else there, even though I repeatedly (4 or 5 times) checked the registry and couldn't find anything left. Anyway, after trying all the "fixes" I could find on the internet, I installed the new Nero software, hoping it might do the trick. During the install, a dialog box came up and said that the upper/lower filters were corrupted but it had fixed them. Once I restarted the system, my DVD player was rarin' to go! I will uninstall the trial version of Nero and reinstall the original version that came with the DVD player now that my DVD is working (and I won't be deleting any "stray" Nero files anymore) but I copied my install CD to my hard drive this time, in case the DVD player goes kaput again.
Just for posterity, here's what I had tried before I found my "solution:"
1. Deleted upper filters in the registry (there were no lowers).
2. I uninstalled then deleted all (checking hidden, too) Itunes, Quicktime files, all HP (for my printer) files, checked for any Roxio files (none). (These were all referenced on various sites as software that is known to cause registry errors, usually once they've been uninstalled, but other times by just being there) Restarted. Still doesn't work.
3. Checked in the bios, it's there just fine.
4. Restored to a couple of different dates, (but it finished by saying it could not restore).
5. Uninstalled the device, turned off the computer, disconnected the power, ide, & cable to graphics card. Turned back on. Turned off again, reconnected everything, turned back on, it told me I had a new device, but turned up with same message.
My next step was going to be to start up in Safe Mode, and then try to do another system restore. This probably would have worked also, as long as I went back to a date before I deleted my apparently critical Nero files. But installing another version of my original software did the trick, and I actually preferred this solution over restoring. Hope this will help someone else if they run into the same problem. Thanks for allowing me to post!
Edited by Moki, 01 March 2008 - 01:46 AM.