Are the .Net components that were compiled against the .NET Framework 3.5 bundled on a system that only has the .NET Framework 4.0 installed?
Or, in other words, contains .Net Framework 4.0 Installer.Net Framework 3.5?
The .NET 4.0 installer does not include the .NET framework 3.5. There is some information on this in MSDN:
The .NET Framework 4 is very compatible with applications that are created with earlier versions of the .NET Framework, with the exception of some changes that have been made to improve security, standards, correctness, reliability, and performance.The .NET Framework 4 does not automatically use its version of the common language environment to run applications built with earlier versions of the .NET Framework. To run older applications with the .NET Framework 4, you must compile your application with the target version of the .NET Framework specified in the properties of your project in Visual Studio, or you can specify the supported runtime using the <supportedRuntime> Element in the application configuration file.
The .NET Framework 4 is very compatible with applications that are created with earlier versions of the .NET Framework, with the exception of some changes that have been made to improve security, standards, correctness, reliability, and performance.
The .NET Framework 4 does not automatically use its version of the common language environment to run applications built with earlier versions of the .NET Framework. To run older applications with the .NET Framework 4, you must compile your application with the target version of the .NET Framework specified in the properties of your project in Visual Studio, or you can specify the supported runtime using the <supportedRuntime> Element in the application configuration file.
<supportedRuntime>
You can install .NET 3.5 and .NET 4.0 together with each other. Visual Studio 2010 also includes improved targeting support for .NET 3.5. ScottGu blog talks about this in more detail.
Of course, it is very old and late. However, sometimes pictures are better than words (assuming links still work).
For more information, see the official Microsoft Page, NET Framework Versions and Dependencies .
In XP SP2 with FW 4 the launch of the FW3.5 application is installed, the message appears:
Unable to find a version of the runtime to run this application.
So the answer is no.
See:. .NET Framework Versions and Dependencies
This gives a clear idea of what is included in each version of .Net. Besides,
You do not need to install previous versions of the .NET Framework or CLR before installing the latest version; each version provides the necessary components.