This phenomena is credited to the way your computer stores files. Once a file is deleted or a drive is formatted, your files aren't lost, they are simply 'ignored' by the drive and may be still recoverable given that you did not overwrite them (e.g. by installing a new OS or reformatting the drive multiple times).
OK, so to recover your files, all you need is to be able to log in to your Windows system and install Recuva.
Recuva is the best free file recovering software, and can recover virtually any lost file. Simply open the program and follow the on-screen instructions.