Hmm, One last thought...
I didnt see that you already tried dskprobe....
That beign the case, sounds like teh drive is "password protected". What I mean by this is most laptops have options to put a password on your hard disk (not to be confused with a BIOS password).
When you boot up with a drive liek this, it would prompt you for a password. And if you dont put the correct password, the drive wont even show up in any tool.
For example, In my IBM thinkpad, I have 2 drives. the main which I boot from, and a 2nd drive in a secondary bay adapter. I keep all my data on