Puran Shutdown Timer is a free utility that can help you shutdown various shutdown tasks on various events. This is an extremely flexible utility.
Schedule shutdown/restart/hibernate/log off/sleep/lock.
You may also schedule opening of a web page or a file.
You can schedule at a paticular time or after some time or at some day and time.
You can schedule at start or termination of a process.
You can schedule if there is no mouse/keyword input for some time.
You can schedule on CPU and hard disk idle too.