string result = String.Empty;
             try
             {
                 ManagementObjectSearcher searcher = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive");
                 foreach (ManagementObject d in searcher.Get())
                 {
                     result = d["SerialNumber"].ToString().Trim();
                     //break;
                 }
             }
             catch (Exception ex)
             {
                 result = ex.Message;
             }