hi, just saying ,if it were mine,done it many time with out ill consequences, i would hold down the power button until it shut down ,and then restart it , totally up to you to try this as there isn't much else you can do .
The power button comes in handy at times like these (held down of course!)
If that power button don't do anything; pull the plug, and remove the battery.
To be really pedantic (after doing what's said above) you could schedule a scan-disk on C: at the next reboot to make sure there's no corruption caused by the immediate power-off. If you don't know how; the ol' search bar will help you. But the OS checks on it's own and will suggest if it think it's needed.