1 gigahertz (GHz) or faster 32-bit (x86) or 64-bit (x64) processor.
1 gigabyte (GB) RAM (32-bit) or 2 GB RAM (64-bit).
16 GB available hard disk space (32-bit) or 20 GB (64-bit).
DirectX 9 graphics device with WDDM 1.0 or higher driver.
http://www.microsoft.com/windows/windows-7/get/sys tem-requirements.aspx