Have an old XP Pro PC with a bad motherboard, and another perfectly good XP Home PC. I put the Pro HD in the Home chassis and (after a revalidation of the OS) it booted successfully. However I can't get to the internet. So I put the old Home HD back in the Home chassis, booted successfully, and attached the XP Pro HD to the Home machine with a USB caddy, thinking I'd just have to copy the files to the Home PC. It sort of recognizes the drive - by that I mean that although no drive ecer shows up on the Computer screen, it makes the bloop-bloop noise when I plug it it (and when I remove it), and if I go to the notification area I can click on the icon for 'safely remove hardware' and it displays as a mass storage device, but there is no drive letter. Disk management displays nothing pertaining to the drive. I've plugged the caddy into the USB port of another PC and have gotten the same non-results. And I tested the caddy with another drive and it works fine. So I'm baffled.... How can I put the Pro HD into the chassis of the XP Home and have it boot and display all my files, yet when I use the caddy it fails to assign a drive letter?