The .NET Framework is a software framework that Microsoft developed. It provides a large library of pre-built functionality (code that you can use to do things), a virtual execution environment (the runtime), and a variety of tools for building applications. It supports a wide range of programming languages, including C#, F#, and Visual Basic .NET.
: This specific version (4.0) is often required to run older software that was built specifically for that environment. Without it, many older "classic" Windows tools and games will fail to launch. Side-by-Side Execution net framework 4.0.30319.rar