title: ASP.net Version 4 with IIS7
body: <p>I am currently developing an ASP.net application which was started in version .Net framework version 3.5. This worked fine without problems. However, I have now realised I need to use .Net framework version 4. When I change the project to be a .net 4 application and I try to run the web app from visual studio 2010 it displays</p>
  
  <blockquote>
    <p>Unable to start debugging on the web
    server. See help for common
    configuration errors. Running the web
    page outside the debugger may provide
    more information.</p>
    
    <p>Make sure the server is operating
    properly...</p>
  </blockquote>
  
  <p>I have changed the application pool for the web app to be .Net version 4 with integrated code. Visual studio still displays the error and when I try to run the web app from outside visual studio, directly running it from the browser I get an IIS error message which says </p>
  
  <p>HTTP Error 500.21 Internal Server Error
  Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list</p>
  
  <p>This is running IIS7 on Windows 7. </p>
  
  <p>Does anyone have any solutions as to how I can fix this problem </p>
  
  <p>Thanks for your help</p>