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.
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.
Just the opposite of that workstation cluster back in university. They had an account named "shutdown" that did exactly that. It had no password and was network-accessable...
even so, it's stupid, you need to apply an update?, shutdown the pc in your work when you're in your home?, you are being idk hacked and need to shutdown everything?
It's simple: if you're a person that's supposed to be shutting down that computer, you'll be able to. If you're encountering the message, you're using the wrong account, or you're the wrong person to be doing that. Switch accounts, or call up the right person.
Non-privileged users of such systems shouldn't care about updates or whatnot. They're there to do their work not mess with the system managed by someone else.