title: Changed framework version results in: Could not load file or assembly PresentationFramework?
body: <p>I am working on WPF application, which was first targeted to 3.0 framework. When I tried to make it work on 4.0, I got following Exception.</p>
  
  <blockquote>
    <p>System.IO.FileNotFoundException was
    unhandled Message: Could not load file
    or assembly 'PresentationFramework,
    Version=3.0.0.0, Culture=neutral,
    PublicKeyToken=31bf3856ad364e35' or
    one of its dependencies. The system
    cannot find the file specified.</p>
  </blockquote>
  
  <p>If I compile application using .Net 4.0 it is working fine. But 3.0 exes are not working with 4.0.</p>
  
  <p>Thanks in advance.</p>