Try trashing the "Audio CD Settings" Pref file ,the "AppleCD Audio Player Prefs" file and the "CD/DVD prefs" file located in the "Prefrence" folder which is in the "System" Folder on the Mac HD.Empty the Trash , and restart the Mac.If your still not able to read CD's , try to boot off of a supported Norton Utilities CDROM , by holding down the letter “C” on your Mac Keyboard as you restart the Mac.Run “Disk Doctor” and it may find a bad extension file.Your CD/DVD Extension file may be corrupt.Nortons may not be able to fix the file , but will make a “alias” of the corrupted file so you can at least find it.Once you find it , trash it ,and reload it off of your Mac Install CD.If Nortons is able to fix it , try restarting and see if the CDROM drive now works.