FOR WINDOWS XP: 2.0 GHz P4 processor or equivalent, 512 MB RAM, 128 MB Video Card, with support for Pixel Shader 2.0, at least 6 GB of hard drive space FOR WINDOWS VISTA: 2.0 GHz P4 processor or equivalent, 768 MB RAM, 128 MB Video Card, with support for Pixel Shader 2.0, at least 6 GB of hard drive space