title: How to check the system is Windows 7 or Windows Server 2008 R2 in Wix Installer?
body: <p>I am working on a windows installer project. And now I only want the software only can be installed on Windows 7 or Windows Server 2008 R2 system, I tried to use this:</p>
  
  <pre><code>&lt;Condition Message='Windows Server 2008 R2 or Windows 7 is required'&gt;(VersionNT = 600 AND ServicePackLevel = 1) OR VersionNT = 601 &lt;/Condition&gt;
  </code></pre>
  
  <p>but it can still be installed on Windows Vista. Please help!</p>
  
  <p>Thank you!</p>