Microsoft C# is a programming language based upon C and C++ which conforms to the Common Language Infrastructure (CLI). Other languages that conform to CLI are VB.NET and J#.

The Microsoft .NET framework is spread across several languages, including Visual Basic, C# and J#. At its core lies a language-neutral framework, the Common Language Infrastructure (CLI), that primarily consists of a Common Intermediate Language and a Common Language Runtime (CLR). The CLI is effectively the .NET equivalent of a Java virtual machine (an interpreter) but, unlike Java, which is a highly portable language, .NET is intended solely for Windows-based systems. Ultimately, .NET has nothing whatsoever to do with C++. The C# language is based upon C++, but other than that they have absolutely nothing in common -- they are completely independent languages.

Visual Basic has always been an object oriented language. VB.NET is no different, but it also conforms to the Microsoft Common Language Infrastructure (CLI) which allows VB code interoperate with other CLI languages including C# and J#.

Yes, C is a common programming language.

No, they are not the same thing.

.NET (dot net) refers to the .NET Framework that can be utilised by any programming language that conforms to the Common Language Infrastructure (CLI). The .NET Framework is primarily composed of the Common Language Runtime (CLR) and the Framework Class Library (FCL).

Visual Basic .NET (VB.NET) is just one of many CLI-compliant languages available. VB.NET is dependent upon .NET.