[AccessD] Lock-screen inside an Access app

A friend asked me how he could put a Windows-like screen lock (that asks for
a password) inside an Access app. He's thinking that it's a hidden form that
then appears after x minutes of inactivity and wants a password before
letting the user back into the app. Presumably it would shut the app down
with no valid password.

Does anyone have an idea how to do this?

TIA,
Arthur