C#

private void lnklblLogIn_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
    sp.Stop();
    frmLogIn LogIn = new frmLogIn();
    LogIn.Show();                     
}

private void btnLogIn_Click(object sender, EventArgs e)
        {
            OleDbConnection con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Users\\John\\Desktop\\Database1.mdb");
            OleDbCommand com = new OleDbCommand("SELECT UserName, PassWord FROM Table1",con);
            OleDbDataReader reader;
            
            bool permit = false;

            try
            {
                con.Open();
                reader = com.ExecuteReader();
                while (reader.Read())
                {
                    if (txtUserName.Text == (reader["UserName"].ToString()) && mtxtPassWord.Text == reader["PassWord"].ToString())
                    {
                        permit = true;
                        break;
                    }
                }

                con.Close();
            }
            catch
            {
                MessageBox.Show("File not able to be read");
                return;
            }

            if (permit != true)
                MessageBox.Show("Username or Password are not correct.");
            else
            {
                Close();
            }
                
        }