The .NET Framework is a software framework that has been developed by the Microsoft Cooperation specifically to run on the Windows operating systems. It contains a large collection of a library that helps it execute in a software environment unlike other similar frameworks that do so in the hardware environment. The .NET Framework is a combination of the Common Language Runtime (CLR) and Framework Class Library (FCL). Together, they are basically responsible running of your PC. The .NET Framework is used in all application created for Windows platform. Follow this link for the .NET Framework V4.0.3019 Download.