The .NET Framework is a popular development platform for building apps for Windows, Windows Store, Windows Phone, Windows Server, and Windows Azure. The .NET Framework platform includes the C# and Visual Basic programming languages, the common language runtime, and an extensive class library.
Microsoft .NET Framework 4.5
Microsoft .NET Framework 3.5 (SP1 latest)
Microsoft .NET Framework 3.0 (SP2 latest)
Microsoft .NET Framework 2.0 (SP2 latest)
Microsoft .NET Framework 1.0 (SP3 latest)
The .NET Framework version redistributable package includes everything you need to run applications developed using the .NET Framework.
If you're looking to run a specific application that requires the .NET Framework, be sure to read its requirements carefully. There are multiple versions of the .NET Framework, and the application may only run on one of them.