I have two MacBooks with downloaded programs called KJams which is a Karaoke program. After downloading the programs I have been using them for almost a year. Each Mac has a different DVD in them the one with the Optiarc DVD RW AD-5960S is still operating correctly and ripping the CD+Gs to KJams program. The one with the HL-DT-ST DVDRW GS21N has stopped ripping the CD+Gs to my KJams program. The ones that were ripped earlier are working correctly. Can someone tell me if I might need a different DVD?