I have 3 internal hard drives, two of them are runnning Windows 7 and they recognized my DVD/CD, but all of a sudden my Windows XP does not recognize the DVD/CD drive. Device manager shows it without an error indicator and says that it is working fine.
Sounds like it may have lost it's drive association or things it's a drive letter that goes to one of the other drives. Right-click My Computer, select Manage. Storage, Disk Management, find the disk drive and assign it a different and free drive letter, see if that works.