ExecuteReader: Connection property has not been initialized.

Hi,

I am designing a login page using C#.net as front end and MS ACCESS 2007 as back end. During runtime I get an error "ExecuteReader: Connection property has not been initialized." following is my code. Please help me.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Data.Odbc;

namespace Accounts
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            textBox1.Text = "";
            textBox2.Text = "";
        }

        private void linkLabel2_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
        {
            Form2 a = new Form2();
            a.Show();
            this.Hide();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string conStr = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\\register.accdb";
            OleDbConnection con2 = new OleDbConnection(conStr);
            con2.Open();
                OleDbCommand cmd2 = new OleDbCommand("Select Table_name from register where User_name='"+textBox1.Text+"' and Password='"+textBox2.Text+"'");
               // cmd2.ExecuteNonQuery();    
            OleDbDataReader dr = cmd2.ExecuteReader(); 
  
                if(dr.Read())
                {
                    if (textBox1.Text == dr["User_name"].ToString() && textBox2.Text == dr["Password"].ToString())
                    {
                        MessageBox.Show("login successfull");
                    }
                    else
                    {
                        MessageBox.Show("invalid password and id");
                    }
                }

                con2.Close();
        }
    }
}