Pioneer DVD.RW DVR-K16D can't read dvd's, only cd's

Hi. I got a Pioneer DVD.RW DVR-K16D on my Vaio VGN-FJ250F that can't read dvd's, only cd's. It plays really well the cd's, and it burns it, but when I insert a dvd, it seems that there's nothing on the drive, because it appears the message: "Insert a disc on the drive". My question is: is my drive failing? or its something about the drivers or the firmware?
Oh, by the way, I got Windows XP.

Please, any suggestion will help. Thanks a lot.