How to send message to MSMQ public queue?

  The queue does not exist or you do not have sufficient permissions to perform the operation.

   at System.Messaging.MessageQueue.ResolveFormatNameFromQueuePath(String queuePath, Boolean throwException)
   at System.Messaging.MessageQueue.get_FormatName()
   at System.Messaging.MessageQueue.SendInternal(Object obj, MessageQueueTransaction internalTransaction, MessageQueueTransactionType transactionType)
   at System.Messaging.MessageQueue.Send(Object obj)

	private static string queueName = @".\test_queue";   
	static void Main(string[] args)
	{
		try
            {
                MessageQueue msgQ = new MessageQueue(queueName);
                string sMessage = "Test MSMQ Message 2";
                msgQ.Send(sMessage.Trim());
                System.Messaging.Message[] MSMQMessages = msgQ.GetAllMessages();

                foreach (System.Messaging.Message msg in MSMQMessages)
                {
                    byte[] data = new byte[1024];
                    msg.BodyStream.Read(data, 0, 1024);
                    string strMessage = ASCIIEncoding.ASCII.GetString(data);
                    Console.WriteLine(strMessage.Trim());
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }