.NET is a library with computer code that is required by other applications. Some programs are made using NET programming language and this update ensures that these applications can be installed and used on your computer, otherwise you will see an error or a message to install it.
The .NET Framework 2.0 is a remarkable union of countless technologies, which maintains compatibility with Win32 and COM. It was released in 2005 to stimulate the wave of Windows Vista and WinFX technologies, including the Windows presentation, communication and work flow groundwork. It is featured into numerous components like virtual machine that is in charge of executing of managed code.