I installed S Iwojima in XP but when I have started the game, it shows this message: "Direct3D doesn't support: Vertex shader 2.0". What should I do?
You are trying to run a product that requires advanced features related to your graphics card. In your case, your GPU does not have Vertex Shader greater than 2.0. Most likely, you have a graphics card with Vertex Shader 1.1. There is nothing to be done except the actual replacement of your graphics card with an advanced one.