How Do I make use of an empty partition?

[seriousgamer]

Basically the guy who did work on my computer a couple years ago made a partition out of my 500gb harddrive here are the pics. As you can see my C drive is almost full and the "backup" folder is like almost empty. I don't even know what is on it. I have all my data backed up on the external seagate

How do I make the "empty" partition usable for same things on my C drive (programs, movies, music, etc)

 

[seriousgamer]

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