Client Object Model Solution Issue due to framework 4.5 version: The type or namespace name 'SharePoint' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?

Solution:

Whenever we create a new project(console,wpf..etc) in Visual Studio 2010,It is targeted to use .net framework 4.0 and SharePoint 2010 need .net framework 3.5 as Target framework.
So solution is simple just go to the properties of your project and change Target framework to .NET Framework 3.5 and you good to go.