I have CDR drive - used to work fine then stopped working. I could see it in My Computer and in device manager but it would not burn or play CD's. The light would come on when the CD hit the tray, but then nothing. Changed the ribbon and it started working fine, for a while. Then it stopped again with the same symptoms. Changed it from primary slave to Secondary master and it worked fine. Then it stopped working again - same problem. I can't figure out why it keeps doing that. HELP!!!