I am running Mac OS 10.4.2 on a 1 gHz Powerbook with an Apple SuperDrive. Recently, some professional movie DVDs (haven't burned any myself) received from Netflix won't mount. When the drive was working normally, the DVD would mount first and then the DVD player would start. Now, the DVD player starts, but the disc never mounts and the DVD doesn't play. Other CDs mount like normal, but several movies will not mount. This happened in the past, and was solved by removing several Stuffit Pro startup files. All these are now gone, and the problem remains. Thanks for any help you can give me.