The approach used here is really a simple one. We intercept the mouse and keyboard activities of the user by hooking into the OS s mouse and keyboard events using the API SetWindowsHookEx(). It is important to note that the hooks we are installing are system-wide. i.e. we receive notification even when our application does not have the focus. This is necessary since we are interested in system-wide user activities, not just in our own application. In these notifications (both keyboard and mouse), we update a common variable that stores the time when the event occurred. Therefore, to get the duration since the last user input, we simply compare the current time against this value.-The approach used here is really a simple on e. We intercept the mouse and keyboard activiti es of the user by hooking into the OS s mouse and ke yboard events using the API SetWindowsHookEx ( ). It is important to note that the hooks we are in stalling are system-wide. ie we receive noti that training even when our application does not hepatitis A. e the focus. This is necessary since we are inter ested in system-wide user activities, not just in our own application. In these notifi cations (both keyboard and mouse), we update a common variable that stores the time when the event occurred. Therefore, to get the duration since the last user input. we simply compare the current time against this value.