Acturally when we format a disk, the Operating System erases all bookkeeping information on the disk, tests the disk to make sure all sectors are reliable, marks bad sectors (that is, those that are scratched), and creates internal address tables for later uses to locate information. Every hard disk should be formatted before using; it is the process of preparing a hard disk or other storage medium for use, including setting up an empty file system.
What pity is that Windows supply one key to format, but no key to unformat, because we can't retrive data from the formatted disk. we should use certain format recovery software to retrieve data. I happened to encounter this situation, the data recovery software I used is easeus data recovery wizard, I don't know what happened to you or someone else, I hope the software I used could help you everybody.