Create 30 day Trial Version
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/1525378/how-can-i-make-my-product-as-a-trial-version-for-30-days">how can i make my product as a trial version for 30 days?</a>  </p>
</blockquote>



<p>I want to create a 30 day trial version of my software, I can record the installation date and compare it with the sysdate of the machine. The problem is how to validate that the user changed the sysdate and how much time I have to adjust in my trial period.</p>

<p>One option is to consume a web service, but the problem are the offline customers. </p>

<p>This is stand alone windows application. </p>

<p>Is there any method I can use to count XX days since the installation?</p>
