You are going to have to either cut the power to it (pull the plug and/or the battery) or wait for it to run out of power, if on battery only. Once shut off, leave it off to charge.
Once it has charged, start it up in "Safe Mode" so you can check to make sure nothing is wrong. You will have limited access in "Safe Mode" so it won't let you do everything. Once you have checked out the system, restart it to get out of "Safe Mode".
How to enter "Safe Mode" when booting the computer.
In Windows 8 and 10...
As your computer restarts, press F8 (possibly a few times) to enter "Safe Mode"
a. Press the "F4" key to Enable "Safe Mode".
(The computer will then start in "Safe Mode" with a minimal set of drivers and services.)
b. Press the "F5"...