Error to Detect, hardisk must be formatted

Question

I have external hard disk 2.5" SAMSUNG HM120JC with 120 GB. When I connected into my laptop/PC, this hard disk can be found as a local hard disk. Then i double clicked this drive (hard disk), my laptop/PC asked me to format it. In this case i need the data inside (117 GB). What should I do? I've tried to use some recovery softwares, but they didn't work. So what's wrong with my hard disk?Thanks