The older versions used to use a type of "undelete".
The new versions have an actual file recovery program but it's not going to work very well, or if at all using a USB connection.
Any data recovery program that scans the drive on a sector by sector level needs direct BIOS support to the drive and USB does not provide that because it's almost all software driven.
Can you explain what happened?
Do you feel the drive is still in good working condition or was the hard drive going bad for a while with bad sectors and other problems.
Or did you maybe just "loose" access to the drive after a crash or other something?
Dave