a blank disk
would say it's unreadable, if you burn something to it, it will become readable.
autoplay may have been disabled, maybe you uncheked a box when it asked a while ago. iirc in MPC autoplay is disabled, turn it on here:
the files would only be .wav if you or someone else made them wav, cd audio just uses the cda file as a link to the data on the disc rather than being the actual sound itself. mayeb this was an early attempt to stop people just compying the data straight off a cd / piracy?