title: Could DigitalProductId and InstallDate ever change?
body: <p>I have a software activation logic which relies on thre parameters:</p>
  
  <ol>
  <li>HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\DigitalProductId</li>
  <li>HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\InstallDate </li>
  <li>Id of system volume</li>
  </ol>
  
  <p>I'm interested in question: <strong>could these parameters ever change under any conditions except manual modification of registry values (for 1, 2) in single OS installation?</strong></p>
  
  <p>System volume id, as far as i know, can change only when the volume is formated. 
  Both DigitalProductId and InstalLDate also should be constant in single OS as they identify a license (concrete windows installation) and the date the OS was initially installes respectively. So according to this logic they shouldn't ever change.</p>
  
  <p>I want to find any documentation that proves these points. Unfortunately my searching for such a documentation didn't give me enough as all that i've found are articles like this <a href="http://technet.microsoft.com/en-us/library/cc709644(v=ws.10).aspx" rel="nofollow">http://technet.microsoft.com/en-us/library/cc709644(v=ws.10).aspx</a> which contain inderect information on the topic.</p>
  
  <p>Also i've looked through this great post: <a href="http://siginetsoftware.com/forum/showthread.php?596-Investigating-the-Microsoft-Digital-ProductID-(DPID" rel="nofollow">http://siginetsoftware.com/forum/showthread.php?596-Investigating-the-Microsoft-Digital-ProductID-(DPID</a>)</p>
  
  <p>It partially proves my points but doesn't give a 100% guarantee</p>
  
  <p>I repeat a question here once again:</p>
  
  <p>Could parameters 1-3 ever change in single Windows installation? </p>
  
  <p>Thanks in advance</p>