Accidently put on second screen only

[Bowl of Rice]

I hit second screen only and thought restarting the computer would fix it stupidly, now when I turn on the computer it boots and its just a random color on the screen how do I get the screen back (Windows 10)

Is taking out the battery/not charging and just letting it sit there for awhile a viable option as it might forget start up settings?

 

[webworkings]

Have you tried completely disconnecting the external monitor and rebooting?