Dell XP DVD won’t recognise CD’s.

On a Dell XP Home PC, the Phillips DVD+RW DVD 8631 drive will no longer recognise CD’s, it will recognise and play DVD’s. The only error message is “no disc in drive”. According to “My Computer” the drive is working properly. Have tried running through all the relevant diagnostics , the only thing I haven’t tried is updating the drivers, I would like to know if anyone else has had the same problem and what their fix was. It is running Service Pack 2.