problem in database connectivity

 private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
             try
            {
                string sconnection;
                sconnection = "provider=microsoft.jet.oledb.4.0;" + "data source=intuitive.mdb";
                OleDbConnection dbconn;
                dbconn = new OleDbConnection(sconnection);
                dbconn.Open();


                OleDbCommand cmd = new OleDbCommand();
                OleDbDataReader dr = null;
                dr = cmd.ExecuteReader();
                 
                cmd.CommandText = "select * from table";

              //  dr = cmd.ExecuteReader();

                string userText = textBox1.Text;
                string passText = textBox2.Text;
             

                while (dr.Read())
                {
                   if (this.CompareStrings(dr["username"].ToString(), userText) &&
                        this.CompareStrings(dr["password"].ToString(), passText))
         
                    {
                        MessageBox.Show("OK");
                    }
                    else
                    {
                        MessageBox.Show("Error");
                    }

                }

                dr.Close();

                dbconn.Close();

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
    }
}