Windows 8 Developers Preview downloads
Go to below URL and download it:- http://msdn.microsoft.com/en-us/windows/apps/br229516/ System Requirements Windows Developer Preview works great on the same hardware that powers Windows Vista and Windows 7: 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 Taking advantage of touch input requires a screen that supports multi-touch To run Metro style Apps, you need a screen resolution of 1024 X 768 or greater