How to run ASP.NET 4.0 version's Websites or Source codes on Microsoft Visual Web Developer 2008 Express Edition(ASP.net3.5), instead of VS 2010?

Just for clarification: you can have problems with the version of Visual Studio only in development.

You only need redistributable .NET Framework if you only need to run and even to build the application. The C# and VB.NET compilers and all the build tools come with the framework. To build without the Visual Studio, use

MSBuild.exe solution-file.sln [options]

For further detail, see http://msdn.microsoft.com/en-us/library/ms164311.aspx[^].

The location of MSBuild.exe depends on the version of framework. You can always find this location in the registry. Use the keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSBuild\ToolsVersions\3.5
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSBuild\ToolsVersions\4.0
(and so on...)

—SA