Reformat or formatting won't make the data in your hard disk erased permanently. Those formatted files are still stored on the disk just invisible or inaccessible. Only the FAT or NFTS table erased the information about where those data were saved but the real data are still intact there in sectors of the disk.So as long as those data are not overwritten by new data, it's highly possible to recover them. And the MOST Effective way is to rely on some format recovery
programs. Recommend you have a try of Wondershare Data Recovery - Format Recovery. It should help.