I've just had a similar experience in my Acer Vista laptop. One out of 10 CDs simply isn't recognized (although I'm positive it was recognized yesterday. This is using the program iTunes. The same exact (and clean) CD IS recognized in my Acer XP laptop, no problem. Put it back in the Vista laptop, and no show.

I put it down to a 'JOOT' (Just One Of Those things).

Good luck,

robo