I have XP Pro running and suddenly my dvd player does not appear in my system tree so, of course, I'm unable to use it to play dvd's. It does appear in the Device Manager without any warning flags (this device is working properly)and I have tried uninstalling it and rebooting. Then it re-installs it but it still doesn't appear in the system tree and is unusable. Please advise.

Is this the same drive, the DVD-E616P that you posted on earlier?

If so, from the Asus support site;

The drive cannot be found on "My Computer" and "File Manager"?
Please try the following steps:
1. Shut down the PC. Disconnect the power cable, remove the computer case cover and check to ensure that the jumper setting on the rear of the drive does not conflict with other IDE device.
2. Check whether the auto-detect function under BIOS is enabled to recognize the drive.
3. Go to "Device Manager" to ensure the IDE controller is functioning properly.
4. If none of the above helps, please contact your local dealer for service.

Find motherboard info on tag on board....Go to website for the motherboard manufacture lookup driver updates for Ide or chipset this might work...have to open case to toread info on tag