In Explorer, right click the drive and choose format.
I have an internal harddrive and put it into my external enclosure. It was originally my primary harddrive for my computer, and still contains window files and such. It is in NTSF. I want to give the harddrive to my dad. I tried deleting everything, such as the window files, but it is not letting me. How would I delete everything inside the harddrive, or clean everything?