Do note that if you have overwritten your files after deleting them, then you cannot recover the files. Use the HDD containing the deleted files as a secondary disk in another system for improving chances of recovering the files.
It's best to have some file recovery software already in place on your PC at all times, rather than waiting for disaster to strike and then looking for emergency solutions. There are powerful programs available that can recover files deleted even over a network, so there is no paucity of software out there; what is required is a sound data protection plan in place.