What platform are you using and what type of computer. Look below

MINIMUM SYSTEM REQUIREMENTS:

-3d Hardware Accelerator Card Required - 100% DirectX 9.0c compatible 64MB
Hardware Accelerator video card and the latest drivers*

-English version of Microsoft Windows 2000/XP
-Pentium IV 1.4GHz or AMD Athlon XP 1700+ processor or higher
-256MB RAM (512MB RAM recommended)
-100% DirectX 9.0c compatible 16-bit sound card and latest drivers
-100% Windows 2000/XP compatible mouse, keyboard and latest drivers
-4.0GB of uncompressed free hard disk space (plus 600MB for Windows 2000/XP swap file)
-8x Speed CD-ROM or 2x DVD-ROM drive