Since Chaos Theory runs on DirectX 9, you need a proxy DLL that intercepts the fullscreen call.
Unlike modern games that have a "Windowed" checkbox in the video settings, Chaos Theory hides this setting deep within its configuration files. This is the first method you should try, as it uses the game's own engine. splinter cell chaos theory windowed mode
The most effective, reliable methods to achieve windowed or borderless windowed mode are listed below. Method 1: The ThirteenAG Widescreen Fix (Recommended) Since Chaos Theory runs on DirectX 9, you