How to check whether exchange server is installed in a system

string search_term = "Vendor LIKE 'Microsoft%' AND Name = 'Exchange'";
string[] properties = new string[]{ "Version" };
SelectQuery query = new SelectQuery("Win32_Product", search_term, properties );
using (ManagementObjectSearcher search_product = new ManagementObjectSearcher(query))
using (ManagementObjectCollection products = search_product.Get())
  foreach (ManagementObject product in products)
  {         
      //save version
      string version = (string) product["Version"]; 
  } 
}