ZylIdleTimer.NET

ZylIdleTimer.NET is a .NET component which lets you to take actions after a specified system-wide (related to the whole system) idle time or to check the time interval of user inactivity. It peeks at all user events for all applications, and cannot be limited to just your program. It may be used to automatically call a routine to log off the user and exit the application if there has been no activity for 30 minutes. It is intended to shut down your critical application if the user has gone to lunch or home, and left the application running. Any user activity, such as keyboard, mouse, or mouse-wheel in any application program will be considered user activity and will reset the inactivity clock.
System Idle time is the time interval of full user inactivity. In this interval any user action is missing on the computer, like pressing a key of the keyboard or moving the mouse or pressing a mouse button or rotating the scroll.

ZylIdleTimer.NET is written 100% in C# using .Net framework and API calls.