how to make Windows form login logout application with c#

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;
namespace Login_Form_in_Csharp_Using_ProgressBar
{
    public partial class Form1 : Form
    {
        string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["dsn"];
        OleDbCommand com;
        OleDbDataAdapter oledbda;
        DataSet ds;
        string str;
        public Form1()
        {
            InitializeComponent();
        }

        private void btnlogin_Click(object sender, EventArgs e)
        {
            if (txtusername.Text == "" || txtpassword.Text == "")
            {
                MessageBox.Show("Please enter User ID or Password");
                txtusername.Text = "";
                txtpassword.Text = "";

            }
            else
            {
                OleDbConnection con = new OleDbConnection(ConnectionString);
                con.Open();
                str = "select count(*) from login where userid='" + txtusername.Text.Trim() + "' and password='" + txtpassword.Text.Trim() + "'";
                com = new OleDbCommand(str, con);
                oledbda = new OleDbDataAdapter(com);
                ds = new DataSet();
                oledbda.Fill(ds, "login");
                long x;
                x = Convert.ToInt64(com.ExecuteScalar());
                if (x == 1)
                {
                    int y = 0;
                    progressBar1.Visible = true;
                    progressBar1.Minimum = 1;
                    progressBar1.Maximum = 100000;
                    progressBar1.Value = 1;
                    progressBar1.Step = 1;
                    for (y = 1; y <= 100000; y++)
                    {
                        progressBar1.PerformStep();
                    }
                    Form2 f1 = new Form2();
                    f1.Show();
                    this.Hide();
                }
                else
                {
                    MessageBox.Show("Invalid User ID or Password! Try Again!");
                    txtusername.Text = "";
                    txtpassword.Text = "";
                }
                con.Close();
            }
           
        }
    }
}

private void button1_Click(object sender, EventArgs e)
{
if (textBox1.Text == "abc" && textBox2.Text == "123")
{
this.Hide();
new Home().Show();
}
else
{
MessageBox.Show("Wrong Id or Password!!");
}
}


in second part of the question, do u want mdi child form ?