title: How to detect an existing installation of IIS using INNO setup?
body: <p>I am looking for a way to determine if the user already has a version of IIS installed. If he doesn't, I will go ahead and run my IIS installation script. </p>
  
  <p>I know of the exception handling clause where I do :</p>
  
  <pre><code>  try
      IIS := CreateOleObject('IISNamespace');  
    except  
      RaiseException(ExceptionType, ‘IIS not installed. Setup will now install IIS on your machine. ’#13#13'(Error ‘’’+ExceptionParam+’’’ occured)’);  
    end;
  </code></pre>
  
  <p>but for some reason, my compiler version doesn't seem to recognise RaiseException. I also tried including </p>
  
  <pre><code>uses  
  SysUtils;  
  </code></pre>
  
  <p>but the compiler won't recognize SysUtils even. Is there something like a registry key that I can look at to determine whether IIS is already installed or not?<br>
  Any help would be much appreciated. </p>