1. Move the mouse to "top right" corner of your monitor and a menu would slideout from the right side.
2. Click on settings
3. Then choose Power and finally choose Shutdown.
1. Press ALT + F4 on your desktop. A popup would showup.
2. Open the dropdown menu and select Shutdown
3. Then finally click on OK
Use any of the two methods and you would see your window 8 system shutting down immediately.