I have designed an desktop application using C#.net that has many users. Each USer has specific rights. The User logs into the system when the application first starts and the UserID number is stored and used throughout the app., but when they want to change user (UserID) they have to close the system down and start again. How would I go about creating a 'log out' - 'login' function that keeps the main form open but disabled allowing a new user to login?