I have tried the USB drive in alternative machines and the response is identical (even with different Windows OS).
Its been suggested that I try "Recover my Files" - I dont know the software, but will give this a try (though from what you're saying, doesnt sound too hopeful).
I'll look down the Linux option after "Recover my Files" (I've never tried Linux, so dont really understand at the moment your suggestion - but I'll work it out

)
I've never disassembled the USB HD - internally is it just a standard ide drive? So it will currently be plugged into an ide to USB convertor?