title: Cannot run extension commands in WinDBG
body: <p>(Sorry for the analogous question I posted, I've modified it.)
  I'm trying to debug an excutable PE file on windows XP to see how PDE and PTE works in a real system. I've learned that windbg have some commands to see the details. It seems that !pte would be able to see the corresponding PDE and PTE of a virtual address. But I come across</p>
  
  <p><code>0:000&gt; !pte
  No export pte found</code></p>
  
  <p>I did some google work and find that it is an <a href="https://blogs.msdn.microsoft.com/willy-peter_schaub/2009/11/27/common-windbg-commands-reference/" rel="nofollow">extension command</a>, but I don't see any description on how to enable these extensions. It seems that everybody is using it directly except me.</p>
  
  <p>I wonder what I have missed but I couldn't figure out. Could anyone please give me some advice?</p>
  
  <p>Thanks.</p>