If the data is critical, and it sounds like it is.. the first thing I would do is use a software that makes a sector by sector backup or image of that uninitialized drive. That way if trying to make it readable by initializing it should hose it, you have a copy.
After that, if you know that the unititialized drive was at one time formatted NTFS then you might try initializing it with Partition Wizard freeware
But it may be worthwhile to talk to someone well versed in disk recovery. There may even be some dedicated forums around for that specialty.
If you get lucky and the Partition Wizard initialization shortcut works, then the files should be there after doing a non-destructive format as NTFS file system.
Assuming that's what it was to begin with.