The following links will show you how to use Windows® Device Manager to see if your Graphics Card is detected, by checking Device Manaer > Display Adapters.
In the screenshot below you will see Device Manager detecting the R9 Fury X Graphics Card. The more Graphics Cards you have in your system, the more entries you will see under Display Adapters.
Note! If you see a yellow exclamation mark, or an arrow pointing down that means the graphics card has been detected, but there are no drivers installed. If no drivers are installed then the Graphics Card will show as a Basic Display Adapter.