Can you start in "safe mode"?
To enter safe mode:
Turn on PC then immediately start pressing F8 (not a continuous press- quickly press press press - if beeping occurs stop for a second or two then start presses again). if you time it right you should get a screen display which gives you the option to Start Windows in various modes Use arrow keys to select "Safe mode" then press enter.
If you don't get this screen turn off PC and try again.
Once Windows loads you will have a desktop display with "safe mode" in the 4 corners
Then go to Start -- Control Panel -- Appearance and Personalization --- Adjust Screen Resolution
This should get you where you want to be to select your display. Once you have changed and saved your settings restart PC