From Stefan Zimmer:
KwikOff Portable is a free one-click tool for your PC to shutdown Windows, to reboot, or to put Windows into standby mode with just one click. The command is executed immediately or after a safety period of up to 60 seconds - the countdown prevents accidental shutdown. Built-in timer for delayed execution of the function up to 90 minutes. With portable edition you can extract files into your local drive and start running application.