Click the "Previous Windows Installation(s)" check box, then "OK." Click "Delete Files" on the pop-up message box to delete the old Windows files. read more
On the left side of the screen, select Remove everything and reinstall Windows. On the "Reset your PC" screen, click Next. On the "Do you want to fully clean your drive" screen, select Just remove my files to do a quick deletion or select Fully clean the drive to have all files erased. read more