Are you trying to use a game/video that is 3D by any chance? I'd honestly have to double check, but I don't think just any video card can generate a 3D signal, so if you're trying to use 3D functions on a card that was made before 3D came along, you can expect issues.
You can also try doing a complete uninstall of the video drivers, complete with removing the old settings, then reinstalling, but this time doing a custom install and making sure NOT to select the 3D components.
So i opened my pc to clean it and its working but when i watch a video or play a game there is fps drop and sometimes i get error that says c/program files/nvdia/3d vision/ nvscapii.dll is missing or not designed for windows. i installed the latest drivers for my graphics card that is a geforce gt 430 and still the same problem? can you help me please?