title: QDialog not such file or directory - Qt Windows
body: <p>I just installed Qt Creator 2.6.1 based on Qt 5.0. </p>
  
  <p>I'm trying to open a project made on 4.8 but I can't compile it. It keeps showing me errors of "not such file or directory".</p>
  
  <pre><code>error: C1083: Cannot open include file: 'QtGui/QApplication': No such file or directory 
  
  error: C1083: Cannot open include file: 'QDialog': No such file or directory 
  
  error: C1083: Cannot open include file: 'QMainWindow': No such file or directory 
  
  error: C1083: Cannot open include file: 'QWidget': No such file or directory
  </code></pre>
  
  <p>And many more.</p>
  
  <p>I added the qmake.exe path to PATH...do I need to do something else?</p>