Windows</br>OS: Windows XP SP3</br>Processor: 2.4 GHz Dual Core Processor</br>Memory: 2 GB(XP)/ 2 GB(Vista)</br>Hard Disk Space: 13 GB free</br>Video Memory: 256 MB</br>Video Card: NVIDIA GeForce 8500 /ATI Radeon HD 2600</br>Sound: DirectX 9.0c Compatible</br>Other Requirements: Initial installation requires one-time internet connection for Steam authentication.</br>