Chances are it's Video Output rendering option is set on "DirectX", whether you might've set it that way, or it somehow ended up that way via some other reason. What you do is set it to "Default and that should stop it from changing Windows' color scheme on ya. I've had this problem as well in the past and this always solved it for me. Even if it's not set to DirectX, but using some other rendering "module" as they call it, try setting to Default. If Default doesn't work for some odd reason you can just try each other one, one-by-one, testing on the same video that you originally were playing when it was switching the color scheme on you, until you find one that works best on your computer.