title: Mouse pad not working in Ubuntu 12.04 on Dell
body: <p>I got a new Dell lap top, and it worked fine for some time, but I think system update did something wrong to the mouse driver. The mouse is no longer showing. 
  I used to be able to fix it with:</p>
  
  <pre><code>sudo rmmod psmouse
  sudo modprobe psmouse
  </code></pre>
  
  <p>Not working anymore. 
  What do I do?</p>