Start your PC in Safe Mode
To start your PC in Safe Mode start tapping the F8 key as soon as your manufacturer’s logo appears. This will open the Windows Advanced Options Menu] •If you begin tapping the F8 key too soon, some computers display a "keyboard error" message or start beeping. To resolve this, pause tapping F8 for 1-2 seconds then start tapping again•If you see the Windows logo, it means you did not start pressing the F8 button soon enough. You will need to reboot and try again.
An advanced options window will open. Select "Safe Mode" by using the Up/Down arrow keys on your keyboard, then press enter.
Wait for Windows to load.
Regular Safe Mode will open Windows with minimal drivers and no internet connection. This is the most recommended method for dealing with viruses and other malware.
When Windows has loaded the desktop will have "safe mode" written in each corner.
Next navigate to Start---- Control Panel----Appearance and Personalization, click on adjust screen resolution.
This is where you should be able to select which display you want. Make the change, click save then restart your PC