Good day greg848,

My first thought was that a USB to SATA adapter (like for external storage) would be a solution, but it depends upon whether your system could boot from a hard drive connected via USB.

My second thought was using Knoppix as the boot method, then recovering that way... However if the system does not see the hard drive, I don't know that Knoppix would be any help at all.

Windows permissions can present troubles when trying to pull data from one hard drive to another, even with 'same' user names, passwords, and OS keys. I know that if you could slave that HDD into a Windows server, the permissions are easily worked around; however I do not understand how unplugging your hard drive made it invisible to the mobo.

Could you have inadvertently disconnected the IDE cable at the motherboard? I do not mean to be insulting, but playing inside a HP Pavilion, I did that once, it was a very compact case.