Or a not so forceful solution: Go into the Ctrl + Alt + Del menu, and press the power button while holding down Ctrl. Now you can do an emergency shutdown.
I remember finding myself in the exact same situation recently. I was sleepier than I ever remember being and the shutdown screen showed an update pending. I compromised for an OFF monitor with the CPU doing whatever it needed to do.
I use "shutdown -s -f -t 0" it forces all apps to shutdown without windows asking you if you want to go back and save or if a program is not turning off.
Not really, it's a pretty simple command that not everyone uses anyway. -s is for shutdown, -t for time. There are more complicated things in the Windows command line interface.
For a more forceful solution: pull the plug out slightly and then arc a screwdriver across the pins. Note: the screwdriver is consumed in this process.
Alternate method: pour mercury into an air vent on the computer.
Someone installed Windows server 2008 on one of our school computers. The shutdown option was missing. So I asked the teacher about it. He also had no idea how the hell to shut it down. Pressing the power button would just log-out the user.
For at least 2 years it did fine with forced shutdowns.