The .NET Framework is Microsoft's comprehensive and consistent programming model for building applications that have visually stunning user experiences, seamless and secure communication, and the ability to model a range of business processes. The .NET Framework 4 works side by side with older Framework versions. Applications that are based on earlier versions of the Framework will continue to run on the version targeted by default.
NOTE : After installing .NET Framework 4, you will need to reboot your computer.
Supported Operating Systems: Windows XP SP3, Windows Server 2003 SP2,Windows Vista SP1 or later,Windows Server 2008 (not supported on Server Core Role), Windows 7, Windows Server 2008 R2 (not supported on Server Core Role).