Sooner or later, now matter how stable your system may be, you will experience the situation where your system completely freezes and you can't do anything, not even call a terminal or log out of the session. In those cases,
Shutdown Windows 8
Windows 8 does no longer provide you with an obvious button to shut your machine down, put it to sleep or restart it. You now have the optoins to either shut down with the Ctrl + Alt + Del screen