Unless you plan on buying a lot of Windows 7 liscences, you should get Home Premium, Professional or Ultimate. Windows 7 Enterprise is the same as Windows 7 Ultimate, except it is meant for those who...
Windows 7 Ultimate offers many more features and security protection.
7 ultimate
According to various websites, all versions of Windows 7 were released for retail sale October 22, 2010.
Get Windows 7 Ultimate installation DVD, insert in the reader and follow instructions.