Here is a potentially crazy idea...
Setup the PC boot into Windows with a password required. Choose a password using only characters that are transmitted to the PC via your joysticks and buttons. Like this:
https://www.ultimarc.com/jpac2.htmlEven if your kids turned on your game, they would need to know the right "magic combination" of joystick/button movements to be able to login and play.
For example, set the password to
12GDRFA, and then use these control panel actions to enter the password:
Start1 > Start2 > Joystick2Right > Joystick2Left > Joystick2Up > Joystick2Down > Player2Button1, followed by Start1+Joystick1Left (which is the Shift command for the keyboard <Enter> key).
Anyone know if that would work?