title: How do I check if Windows Installer 3.1 or higher is installed?
body: <p>I need to know this since this is a pre-req for .NET 3.5 and if I'm including the .NET bootstrapper, I should also see if Windows Installer 3.1 is needed.</p>
  
  <p>Right now I'm checking for the registry key:</p>
  
  <pre><code>HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP3\KB893803v2
  </code></pre>
  
  <p>Which will check for Windows Installer 3.1 but I suspect it doesn't check for higher versions. (Haven't been able to confirm or deny that)</p>
  
  <p>What registry key should I look at to find this information?</p>
  
  <p>Edit: I need to check this in Inno Setup which is what I'm using as my bootstrapper, and I'm not sure how to check a dll version in there.</p>