I'm developing the security side of VB package, and I want to prompt the user to enter a password if the system has been idle for a set time. I dont want to raise an event for the the MDI, for every mouse move & keypress on every dll, and then check this against a permanently running timer. I can't use NT's security system either as the software will be running mechanical tests on aircraft for anything up to 3 months. Is there an API function which would do this?..(surely that's how screensavers are activated!) The security system can't rely on a screensaver application as this could easily be changed and modified by operators. Can anyone please help?