To hide or unhide a file or folder with Command Prompt, you must first run it with admin rights. Open the Start menu and search for cmd. Right click on it and choose Run as administrator.
To hide, enter this command:
attrib +s +h c:\your-file
To unhide, enter this command:
attrib -s -h c:\your-file
The letter C should be changed by the drive letter where your file or folder is located.