Computer not seeing DVD and CD-ROM drives

[abaitken]

I tried to access my DVD drive four days ago and found that my computer is not seeing my DVD drive (TSSTcorp CD/DVDW TS-H552B) nor my CD-ROM drive (LITE-ON CD-ROM LTN-489S). I did a System Restore to the last day that I used the DVD drive. I use Nero for burning. When the computer rebooted, I got an error message window from NeroCheck that said "The LowerFilter or UpperFilter registry key for CD-ROM was containing incorrect drivers. It has been corrected. You must reboot your computer in order the changes are effective. Until then, you may not be able to access your CD_ROM drivers."
I did the reboot, but this did not solve my problem. I ran across this forum and read of a similar problem where it was suggested to use Device Manager to uninstall the drives and then reboot, forcing a redetection of the drives. I did this with no success. Device manager shows a yellow circled exclamation point by both drives. When I double click on either drive, the device status window says "Windows cannot load the device driver for this hardware. The driver may be corrupted or missing. (Code 39)". Any one have any suggestions?
I have a two year old emachines computer using XP Media Center Edition and SP2. Both drives were OEM and have worked flawlessly until now.

[CDR-Zone.COM]