I am a little puzzled as Digerati is
Yeah, we need some more information. The problem is, partitions are handled as if they are separate drives (hence separate drive letters). The partition and file tables keep track which data segment (chunks of files) goes where. When the partitions are deleted, almost all of the data is still on the drive, but the information in the remaining table(s) saying which piece of data goes where is no longer valid. So the remaining tables are not able to piece all the data fragments back together again.
As Embolism correctly pointed out, there are forensic data recovery tools, and even Partition Recovery
tools. But none of these can guarantee 100% success. And this is especially true if the drive has been used after the partitions were deleted.
There are also professional recovery services, but these can be very expensive (into the $1000s!). But depending on the lost data, may well be worth it!
Of course, I am assuming it is the drive with problems and not the dropped enclosure.
At any rate, Taishi_Ci, I hope with the holidays now passed you are able to come back and provide some more information so we can help (if possible) and also so this thread does not go dormant without resolution.