DirectX

DirectX is the family of Windows interfaces that games and multimedia applications use to communicate with graphics, audio, and input hardware. You interact with it indirectly whenever software asks the GPU to draw a scene or play protected media. Running dxdiag shows the installed runtime and the feature levels exposed by the current graphics package. A game can require a feature level that older hardware cannot provide even when Windows reports a recent DirectX version. If an application suddenly stops launching after a display update, compare its requirements, reinstall the graphics package cleanly, and avoid downloading loose DirectX DLL files from unofficial sites; Windows Update and the application's own installer should supply trusted runtime components.