NEC ND-3550A won't read dvds correctly

So I have Windows 2000 and an ND-3550A. In Windows Explorer it says this drive is a “Compact Disc”, even though the device manager says it’s a dvd/cd drive. It plays cds just fine. However, when I insert a dvd, it reads it, and when I double click the drive it says “Insert a disc in the drive”. ATI’s dvd player doesn’t see a dvd, BUT dvddecrypter sees and reads the dvd just fine! How do I get Windows 2000 to read dvds???