Press and hold the power button. That should force your laptop to shut down.
Restart it. Annoyingly, you'll be back to where you started but press and hold the power button again.
Repeat.
After a few times of forcing a shutdown you should find that your laptop will then start with a blue screen headed 'Choose an Option'. Select 'Troubleshoot'.
At the next screen, select 'Advanced Options'.
At the following screen, select 'System Restore' and see if you're offered an option to take your laptop's registry back to a date before the problem occurred.
If System Restore either isn't available or doesn't fix the problem, start as above again but when you get to the screen where you previously chose 'Advanced Options', choose 'Reset this PC' instead. Then choose the option to retain your files. (That's more drastic than 'System Restore' because it will remove any programs/apps you've installed on your computer, meaning that you'll need to reinstall them. However your documents, images, videos, etc will still be there).