I have two identical computers. Each one has ASUS P5K Pro and running XP Pro. On one computer the DVD works fine. On the other computer the DVD will not run the CD/DVD disk. I have swapped the drives and the problem remains, so I know it's not the drive. I also reinstalled the driver on the bad machine, and even copied the drivers from the good one to the bad one. Nothing has worked. I am mystified! And stupified! Any help will be greatly appreciated.