Mike's desktop has two drives in an IBM PC and when he went to defrag one, it disappeared from Windows 7. So he can't see it. What can he do? Leo says that try rebooting and see if he can see it on boot up. If not, try using a NewerTek Universal drive adapter to see if you can see it that way. If you can't, then the drive is dead. The good news is, drives are cheap. Leo recommends putting an SSD drive for your main drive and use the good hard drive for the backup. You'll get a huge boost in speed that way.