S Lock is designed as a security feature for those of you wanting to prevent unauthorised users from using your computer. It also disables CTRL+ALT+DEL, ALT+TAB, CTRL+ESC, along with the most commonly used key combinations.This stops a user completely from stopping the program unless they have the passcode. (PLEASE NOTE: The key combinations are enabled again once the key has been entered correctly and the program is unloaded).