Google for Getdataback.
In the mean time, do not use that drive. Do not install anything on it whatsoever.
Formatting a drive doesn't actually delete the data, it just wipes the file allocation. Then, the sectors are overwritten bit by bit as the drive is used again. So, the more you install, the more you lose.
You probably already know, but it's a vital thing to keep in mind when trying to recover data.