Why old version of Asp.net Application not working in Newer Visual Studio ?

We had older version asp.net application that was developed in Visual Studio 2005. The Application was not working in higher version of Visual Studio like Visual Studio 2008 and 2010. The project and the entire application got hanged when we start running project. Application was hosted in local computer with IIS at folder path C drive under inetmgr folder wwwroot folder. All the pages also working expect url rewriting but project and visual studio were getting hanged every time. It was very strange error but it was solved with configuration settings in IIS

Solution: We have to just change one thing in IIS for above error that is Go to Basic Setting for the Website. Than Appropriate Application Pool for the Application. Application was developed in Visual studio 2005, and its framework was 2.0, so we changed the Application Pool to the Version 2.0 and automatically all the errors got solved and even url rewriting error also solved.