hard drive contact error

I'm totally stuck. I had two drives going. no problems.Then I needed to
format one, so I could re-install win XP. Ok. done it before.Only the drive
to a long time to format. Over an hour and a half and still 0.0% , this was
tried twice same deal. fine. this drive is fried. enter new hard drive.
install ok only, the old drive which had it all shows unformatted. here's the
strange bit. It's a 100gig drive. 46gig used 54gig open. 46 gig locked out
54gig found and working. all the used data states is an unkown file system
and a RAW drive. THE DATA SPACE IS RAW !! IT'S FREAKING DATA !! The question
is how do I get it back? How can I change or reset a fileing type? How do I
tell my system " Hey,there is data here, Look at it," Any help would be
greatly needed. I've got seven month of irreplaceable work on the line.
Please Help !