How to change my screen from command prompt

I updated my windows from 32 to 64 bit. After I opened my laptop and started to install some windows I got a notification that told me that I had to restart my laptop, so I did it. It started as normal, the windows logo showed up, no errors, nothing wrong but I couldn't see the desktop and I know why. For some reason my laptop thinks that it has 2 monitors (which I don't) and so I think it is showing the fake monitor which has nothing, no background, no icons,no taskbar, only the mouse mouse. So I don't really have access over my computer, besides comand prompt from "windows repair". Please what can I do?