title: Launch associated program or show "Open with" dialog from another program
body: <p>Under Window Seven, the following command displays a dialog box then terminates without any other action, why?</p>
  
  <p>The expected effect is launching the associated program <code>Notepad++</code> or at least <code>Notepad</code></p>
  
  <pre><code>RUNDLL32.EXE SHELL32.DLL,OpenAs_RunDLL D:\doc\toto.txt
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/mYPSU.png" alt="enter image description here"></p>