New
#11
You do realize changing the drive letter is a OS specific thing - it has nothing to do with the drive itself. Drive letters are a windows association of a drive letter to a specific device (drive signature) - it doesn't follow the drive. Moving the drive to another computer, changing the drive letter, then moving the drive back changes nothing.
I couldn't tell from the OP description whether this ever worked on Windows 7. If not, I think it is a case of a missing device driver. google for Windows 7 drier for your specific enclosure.