Features:
-64-bit versions Combines remarkable ease-of-use with the entertainment features of Home Premium and the business capabilities of Professional–get it all with with Windows 7 Ultimate
-Make the things you do every day easier with improved desktop navigation; start programs faster and more easily, and quickly find the documents you use most often
-Run many Windows XP productivity programs in Windows XP Mode; watch, pause, rewind, and record TV on your PC
-Easily create a home network and connect your PCs to a printer with HomeGroup; connect to company networks easily and more securely with Domain Join
-Recover your data easily with automatic backup to your home and business network; help protect data on your PC and portable storage devices against loss or theft with BitLocker.

List of windows editions available for installation
Windows 7 Home Basic
Windows 7 Home Premium
Windows 7 Professional
Windows 7 Ultimate

System Requirements:
Processor: 1 gigahertz (GHz) or faster.
RAM: 1 gigabyte (GB).
Free space on hard disk: 16 gigabytes (GB).
Graphics card: DirectX 9 graphics device or a newer version.
Additional requirements to use certain features.
To use touch you need a tablet or monitor that supports multitouch.
To access the Windows store to download and run apps, you need an active Internet connection and a screen resolution of at least 1024 x 768 pixels

HomePage - http://www.microsoft.com