Useful Free Software : Find and delete duplicate files on Windows Computer for free

We all use our computers to save files, be it documents, music, movies or anything else. As time passes, eventually, our files increases on our hard disk, and so does some amount of duplicate files, which are just lying there unnoticed and occupying unnecessary space. We can clean them, but we may not know exactly where they are. We can find those duplicate files manually too with some search terms, but that may be a tedious task. Luckily, there are software for that!