AUDIO CD DOESN'T PLAY

Since some days ago, the computer is not able to play audio cds.
Windows media player says that it does not find the specified file: "Windows
Media Player cannot find the specified file. Be sure the path is typed
correctly. If it
is, the file does not exist at the specified location, or the computer where
the file is stored is offline."
PowerDVD tells me "error of MCI. An unknown problem has been
produced while the controller of the specified device was loaded", and Real
Player simply does not recognize the CD. Any another type of multimedia
plays OK. I have been looking for help in other forums
and many of them talked about an error of the MCI, concretely of the file
mcicda dll. I have reinstalled the media control devices as explained in
the microsoft help in the web, but it still doesn't work. That file seems
to be integral and perfect.
I must say that I have two drives, a DVD ROM and a CD RW, and when I
disable one of them in the device manager everything works properly, the CD
Audio reproduces itself perfectly. If I enables both, the problems go back.
I have also tested Adaptec's ASPI drivers, the last version, but without
obtaining any result.
I din't change anything in the hardware before it failed.

I have written to you again in case you couldn't read the first letter.

Thank you, Joni