windows – How to secure a computer key that operates a television

I've bought an Intel calculator to turn a TV into a screen.

I configured it to use VNC in the computer to change the display (open windows, movie projection, etc.). It works very well this way, but my concern is to secure it.

It is currently plugged into the back of a television. At this point, anyone can connect a USB mouse / cable and control it. I can not lock the computer because I want the desktop to be viewing (not a locked screen).

Some ideas that I had

  • Require an administrator password when connecting a USB device

    • I do not know if it's even possible. Google did not help.
  • Physically pack the device

    • I have not found anything on the market and the unobtrusive nature of the device means that a box would move the TV away from the wall.
  • Run it as a user with only the necessary privileges.

    • Maybe it's the best option?

What would be the best way to secure this computer?