Some people even do not know that there are 2 video cards installed in their computer. There are discrete (external) and integrated (built-in) video cards. Oh, I've read about the similar problem on. 1. First, go to computer management.
2. Select the Device Manager tab and find the video adapters. 3. Right-click on it and select Disable. To understand what their built-in and what's internal, you can simply drive the video card name in turn into Google search and see what is displayed.