Windows XP, Vista SP2 32-bit, Seven. [Windows up to date and latest service pack installed]
Processor
Dual Core Athlon x2 2.6 GHz or Intel Equivalent
Memory
2 MB RAM
Graphics
ATIÂ Radeon 4850 or NVIDIA GeForce 8800 GT
DirectX®
9.0c
Hard Drive
3 GB HD space
Sound
DirectXÂ Compatible
Other Requirements
Broadband Internet connection
Activation details
Go to: http://store.steampowered.com/ and download STEAM client
Click "Install Steam" (from the upper right corner)
Install and start application, login with your Account name and Password (create one if you don't have).
Please follow these instructions to activate a new retail purchase on Steam:
Launch Steam and log into your Steam account.
Click the Games Menu.
Choose Activate a Product on Steam...
Follow the onscreen instructions to complete the process.
After successful code verification go to the "MY GAMES" tab and start downloading.