What happens when somebody disables the integrative video card then later removes the new card?

well I have this used Laptop, I don't know the owner and this is what happens I turn the computer on but nothing shows on the screen i even connected to another monitor and nothing shows either.



So am wondering if the integrated video card has been disable if so how can I undo it without being able to see the screen.|||Try the monitor toggling button, if that doesn't work then the graphics are probably broken.