I'm running XP Pro. I have a DVD and a CDRW. Things were working great as I just burned a CD a couple of days before, then yesterday I went to burn something using NERO and neither of drives showed up. Looked in MY Computer and they were there...Thought I'd reboot and try again...this time I went to MY Computer and none of them were there...went into Device manager and now they show ! next to the 2 drives. When booting they show up in the boot up sequence. I've tried using only one drive and still get same results. I tried switching the drives around on the different channels...I even dropped a Promise ATA66 Controller card in and tried them on that...in all cases they show in boot process..but windows has a problem with them....