Minimum:

OS: Windows XP SP2
Processor: Dual Core 2GHz Intel or 2.8GHz AMD
Memory: 2 GB RAM
Graphics: DirectX 10 compatible with 512MB RAM
DirectX?: 9.0c
Hard Drive: 8 GB HD space
Sound: DirectX 9.0c compatible

Recommended:

OS: Windows 7
Processor: Quad Core 2.66GHz Intel or 3.2GHz AMD
Memory: 4 GB RAM
Graphics: DirectX 10 compatible or later with 1GB RAM
DirectX?: 10
Hard Drive: 8 GB HD space