Windows Vista and newer (including Windows 10)
Click 'Start', click 'Control Panel', switch to 'Small Icons' by clicking the drop-down on the top right of the window, click 'Administrative Tools' in the main window, double-click 'Services'. In the window that appears scroll down until the Task Scheduler row appears and select this. On the Action menu, click Start, Stop, Pause, Resume, or Restart.
In Windows 10, you can start Task Scheduler by typing 'task scheduler' in the search box on the taskbar.