Windows Media Player switch mode problem

Hi All,
I’ve been playing music in our office most of the time using media player in a PC which has Windows Vista and suddenly its stop working I don’t really know what’s the cause of this problem.
I tried to configure the said message pop up in my screen and just click the ok button for switching to analog mode but same problem occurred. I’d also tried my other mp3 songs in different kind of CD but nothing happens.
Any suggestions would be greatly appreciated with this matter.
Thanks!
This is the message appear in my screen.

Windows Media Player Performance
Windows Media Player encountered an error when reading the CD-ROM drive in digital mode.
Click OK to switch to analog mode. Click cancel to retry playing in digital mode
