It worked for me on an internal.
I had a drive die on me. If the drive was connected via SATA, Windows wouldn't boot -- it would just hang at the splash screen. Disconnecting the drive allowed Windows to boot normally. DLG wouldn't run on it from DOS -- the drive would disappear as soon as DLG tried to look at it.
I booted with a SystemRescue CD (as suggested by another helpful person around here). The drive was visible/accessible in 'nix -- sometimes.
I managed to copy the data off it (in many sessions... the drive would work for a while in 'nix and then up and disappear while files were being copied -- took about a week to get everything off it).
Glad it worked for you too.