Motion Detection Program Need A Piece Of Software That Will Password Protect A Computer (besides Windows Log Off)?

Need a piece of software that will password protect a computer (besides windows log off)? - motion detection program

I am looking for a room that locks the keyboard and mouse while access to other programs run freely and without interruption.

My goal:
To run the software motion detection with a webcam and video, while still locking people outside delete the saved video without a password.