First, make sure your computer meets the minimum system requirements to run the game:
Operating system: Windows XP;
CPU (Processor): Intel Pentium 4 with 1.7 GHz or similar;
RAM: 256 Mb;
Free HDD space: 1 GB;
Video card: 128 Mb VRAM;
Sound card: DirectX 9.0 compatible;
If the requirements are fulfilled, update your video card drivers and DirectX and reinstall the game.