I have Windows XP and one disk. I added another 160G WD disk. The disk utility copied all the files from disk 0 (the original disk) to disk 1 and made it the new boot disk. How do I make disk 0 go back to being the bootable disk? When I unplug disk 0 , disk 1 boots up just fine. When I unplug disk 1 the computer will not boot up.