Try this -

It took me several days, including trying all the
suggested fixes I could find on the net (including the
Microsoft fix of deleting the registry key), all no help.

My fix was in re-installing the Microsoft MCI CD Audio
device. Here is how I did it:

Go to control panel, go to the add new hardware applet
(not the software add/remove, but rather the add new
hardware utility), select "No, I want to add hardware from
list", scroll down and select "Sound, Video and game
controllers", scroll down and select "Microsoft MCI",
select CD audio device (media control) and select next.
After adding the device reboot your computer.

My Windows Media Player V9.0b then started recognizing the
audio CDs!

I'm still running Windows 98SE.

Good luck!

Darryl