What is best way to remove duplicate files

I have a hard drive that has numerous duplicate files. E.g. certain documents are under My Documents, but also under my music, and also in other place. I want to remove the duplicate, but retain the most recent file. Also, if a duplicate is removed how can I be sure it is removed from the place I’d like, e.g. in the above example I’d like it removed from my music as it is a Word document. What is the best software to accomplish this?