title: Emacs auto-complete installed by Package from http://marmalade-repo.org/ doesn't work
body: <p>I'm new to Emacs and the version is 24.</p>
  
  <p>As mentioned in the title, I've installed auto-complete by <code>M-x package-install</code> from <a href="http://marmalade-repo.org/" rel="noreferrer">Marmalade-repo</a>, and the files lies in <code>~/.emacs.d/elpa/auto-complete-1.4/</code>.</p>
  
  <p>Then I turned Emacs off and opened a new frame, but nothing happens when coding.</p>
  
  <p>Do I need some configuration to make it run?</p>