title: How to detect Excel version programmatically
body: <p>In my installer, I checked the registry key (HKEY_CLASSES_ROOT\Excel.Application\CurVer) to get version of Excel.
  It has worked since day 1. 
  However, recently we find on one client's PC there is no such key and my installer fails.
  So I wonder if there is any other registry key to get version of Excel? 
  Or the client's Excel has some issue?</p>
  
  <p>Thanks </p>
  
  <p>Edit </p>
  
  <p>The client has office 2010 (32 bit), windows 7 (64 bit). </p>