[Shin]

Warning: I will NOT take any of the complaints/shit because you decided to do this.

Step ONE: Open up Notepad.
Step TWO: Type in cmd.exe and save the Notepad file as cmd.bat
Step THREE: Open up the cmd.bat file and type in shutdown -i
Step FOUR: A dialog box should open up, and then do whatever you want. (Don't forget, uncheck the box saying 'Warn users of this action')
Step FIVE: Once it says you can press OK, press OK
Step SIX: There you go, everyone's (including your teacher's) computer should shut down.