.NET FrameWork
All of my programs require the .NET framework to run. This is the underlying architecture of any application programmed using Microsoft's Visual Studio. Recently I've upgraded from .NET 3.5 (Visual Studio 2008) to the .NET 4 RC (Visual Studio 2010 RC). A Microsoft link to the latest .NET download can be found below. Any applications requiring the older framework will run the same with the newer framework.