When I first used Windows 8 I found it unclear how to shut down. Therefore I thought I would list the available options;
To shut Windows 8 down, move the mouse cursor to the bottom right corner of the screen, click the Settings icon – or just hold down the Windows key and press I – and you’ll see a power button. Click this and you get the option to Shut Down or Restart.
Alternately you can press Ctrl+Alt+Del and click the power button in the bottom right-hand corner.
If you are on the desktop you can press Alt+F4 to access Shut Down options.