ms claims that they are
home basic
*1 GHz 32-bit (x86) or 64-bit (x64) processor
*512 MB of system memory
*20 GB hard drive with at least 15 GB of available space
*Support for DirectX 9 graphics and 32 MB of graphics memory
*DVD-ROM drive
*Audio Output
*Internet access (fees may apply)
Home Premium / Business / Ultimate
*1 GHz 32-bit (x86) or 64-bit (x64) processor
*1 GB of system memory
*40 GB hard drive with at least 15 GB of available space
*Support for DirectX 9 graphics with:
oWDDM Driver
o 128 MB of graphics memory (minimum)
o Pixel Shader 2.0 in hardware
o 32 bits per pixel
*DVD-ROM drive
*Audio Output
*Internet access (fees may apply)
Although i would say at least a dual core processor , 2 gb ram and any sort of dedicated graphics card to run if effeciently with aero