Rainbow/Colored Graphics

Hi, I am having trouble ridding a bad video effect described as in the title. I dont know whats causing it. I dont have a bad video card (GTX 970, 4GB RAM), I tried adjusting settings both in the card and in the game, but having no success. I saw a video on youtube a long time ago with the same problem but cant find it anymore. Can anyone help with this problem?

Your post is already here: http://forums.forzamotorsport.net/turn10_postst62795_Bad-Graphics–Video-settings.aspx