Did you try to change the resolution first? Right click between the icons, on the desktop. Then Display Settings. Then "Display Resolution" is down a bit in the right hand side of the window that opened.

Even if that isn't where you have to fix it, there are other things in there that might help (selecting the right monitor model, etc). Or opening the device manager will let you check for drivers that need help (yellow !, or red X, or "unknown device", etc).

Learning computers is a lot of "wonder what happens when I...". Generally you don't want to delete things, but drivers in device manager are an exception. Removing the device just tells the PC to detect it again, and attempt to install it.

Hopefully you have the internet connected/active to be able to get drivers with.