title: WMI query for product id (Serial Number) returns wrong results
body: <p>I wrote a WMI query like below about windows product id (Serial Number) but it doesn't return product ID.What is the reason?</p>
  
  <pre><code>ManagementObjectSearcher searcher =
                     new ManagementObjectSearcher("root\\CIMV2",
                     "SELECT * FROM Win32_OperatingSystem");
  
                 foreach (ManagementObject queryObj in searcher.Get())
                 {
                     Console.WriteLine("-----------------------------------");
                     Console.WriteLine("Win32_OperatingSystem instance");
                     Console.WriteLine("-----------------------------------");
                     Console.WriteLine("SerialNumber: {0}", queryObj["SerialNumber"]);
                 }
  
  
                 return Convert.ToString(searcher.ToString());
  </code></pre>