1. Go to fakeupdate.net
  2. Choose the language (down at page)
  3. Choose the operating system
    • Windows 98
    • Windows XP
    • Windows Vista (Home Premium)
    • Windows 7 (Professional)
    • Windoes 8
    • Mac OS
  4. Set the browser on full screen mode (F11)
  5. Enjoy when your friend is back
    • Works also fine for your boss.

[via Jan Girlich / DomHa]