Windows 10 graphics output to monitor black screen

A co-worker tried to connect a windows 10 laptop to an exteal monitor. The monitor was never picked up in the first place and he right clicked on the home screen, went to graphics output and set it to "monitor". After doing so the laptop screen is now black, and obviously its not showing on the monitor either.

Is there a way to revert the graphics settings with a hotkey or something? If I reboot in safe mode, will it use original settings? How do I force reboot windows 10 into safe mode without having access to the start screen?