I did a search for "SiS video card directx" and found that some of the Microsoft games/simulators are having problems with the SiS drivers. If the latest drivers do not help and if Great Planes/Knife Edge tech support are not able to help then a new video card would be my suggestion. You can buy a GeForce 256 MX? w/64 MB of ram for ~75.00. nVidia has updated drivers at www.nvidia.com. I have successfully been using their "Detonator" driver with several versions video card based on their chipsets.