.NET Framework Fundamentals
The .NET Framework is Microsoft’s latest development platform, and is currently
in version 4. It includes a Common Type System (CTS) and Common Language
Runtime (CLR). .NET Framework applications are written using Object Oriented
Programming (OOP) methodology, and usually contain managed code. Memory
management of managed code is handled by the .NET runtime; this includes
garbage collection.

.NET Framework Applications
Applications written using the .NET framework are first compiled into Common Intermediate
Language (CIL). When an application is executed, the Just-In-Time (JIT) compiles this CIL into native code. Applications are compiled and different parts are linked together into assemblies that contain the CIL.

C# Basics
C# is one of the languages included in the .NET Framework. It is an evolution of previous languages such as C++, and can be used to write any number of applications, including both web sites and Windows applications.

Integrated Development Environments (IDEs)
You can use Visual Studio 2010 to write any type of .NET application using C#. You can also use the free, but less powerful, express product range (including Visual C# Developer Express) to create .NET applications in C#. Both of these IDEs work with solutions, which can consist of multiple projects.