char[] chars = "1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
            char[] first = "TBUO".ToCharArray();
            Random r = new Random();
            string s = "";
            s+=first[r.Next(first.Length)];

            for (int i = 1; i <= 15; i++)
            {
                int j = r.Next(chars.Length);
                s += chars[j];
                if (i % 4 == 0)
                    s += "-";
            }
            MessageBox.Show(s);