[SOLVED] I am used 400GB on my hard drive, windows says I am using 4 TB

[PC guy model 101]

Mostly movies and back ups of programs (in short a back up of my computers non os related stuff).
When I look at the folder holding the data it says 404 GB size, 405 GB disk size, when I look at the whole hard drive it says 3.5 TB of space was used.... No hidden files, and I am grabbing just the data I want and moving it manually.... Help?

 

[USAFRet]

Install and run either WinDirStat, or WizTree.

Run as Administrator, selecting only the drive in question.
Post a screencap here.

Also, a screencap of your Disk Management window.