Strip leading and trailing sequences of "20" from the vendor key.

BulkPrinting/BulkPrinting/Program.cs

 
 #if SIMULATE_HDD_SERIAL
             //Globals.HDDSerialNumber = "9VMTDFGX";
-            Globals.HDDSerialNumber = "2ZRA6NXL";
+            //Globals.HDDSerialNumber = "2ZRA6NXL";
+            Globals.HDDSerialNumber = "B913162785";
 #else
             Globals.HDDSerialNumber = Utility.GetHDDSerial();
 #endif

BulkPrinting/BulkPrinting/Properties/AssemblyInfo.cs

 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
 [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyFileVersion("1.8")]
+[assembly: AssemblyFileVersion("1.9")]

BulkPrinting/BulkPrinting/Utility.cs

             return Encoding.ASCII.GetString(HexStringToBytes(hex));
         }
 
+        public static string TrimRepeats(string value, string substring)
+        {
+            var step = substring.Length;
+            if (step == 0)
+                return value;
+
+            int start = 0;
+            int end = value.Length;
+            while ((start <= end - step) && (value.Substring(start, step) == substring))
+                start += step;
+
+            while ((end >= start + step) && (value.Substring(end - step, step) == substring))
+                end -= step;
+
+            return value.Substring(start, end - start);
+        }
+
         public static string GetHDDSerial()
         {
-            ManagementObjectSearcher managementObjectSearcher = new ManagementObjectSearcher("SELECT * FROM Win32_PhysicalMedia");
-            string result;
-            ManagementObjectCollection.ManagementObjectEnumerator enumerator = null;
-            try
+            using (var managementObjectSearcher = new ManagementObjectSearcher("SELECT * FROM Win32_PhysicalMedia"))
             {
-                enumerator = managementObjectSearcher.Get().GetEnumerator();
-                while (enumerator.MoveNext())
+                using (var enumerator = managementObjectSearcher.Get().GetEnumerator())
                 {
-                    string text = ((ManagementObject)enumerator.Current)["SerialNumber"].ToString();
-                    text = text.Replace(" ", "").Replace(".", "");
-                    if (text != "")
+                    while (enumerator.MoveNext())
                     {
-                        result = text;
-                        return result.Length > 15 ? result.Substring(result.Length - 15, 15) : result;
+                        string text = TrimRepeats(enumerator.Current["SerialNumber"].ToString().Replace(" ", "").Replace(".", ""), "20");
+                        if (text != "")
+                        {
+                            return text;
+                        }
                     }
                 }
             }
-            finally
-            {
-                if (enumerator != null)
-                {
-                    ((IDisposable)enumerator).Dispose();
-                }
-            }
-            result = "SERIAL ERROR";
-            return result.Length > 15 ? result.Substring(result.Length - 15, 15) : result;
+            return "SERIAL ERROR";
         }
 
         public static DBHelper OpenDBConnection()