Useful Windows 8 tips (part 1)

• Lock screen background - http://www.eightforums.com/tutorials/2639-lock-screen-background-image-change-windows-8-a.html
• Log-off, lock, power-off - http://www.eightforums.com/tutorials/2584-lock-log-off-restart-shut-down-switch-user-windows-8-a.html
  (also: http://siryes.blogspot.com/2012/07/logoff-restart-and-poweroff-in-windows8.html)