GUI Windows Form C#

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
public class Form1 : System.Windows.Forms.Form {
    private System.Windows.Forms.Label label1;
    private System.Windows.Forms.GroupBox groupBox1;
    private System.Windows.Forms.CheckBox chk_option1;
    private System.Windows.Forms.CheckBox chk_option2;
    private System.Windows.Forms.CheckBox chk_option3;
    private System.Windows.Forms.CheckBox chk_option4;
    private System.Windows.Forms.Button button1;
    public Form1() {
        this.chk_option1 = new System.Windows.Forms.CheckBox();
        this.label1 = new System.Windows.Forms.Label();
        this.chk_option2 = new System.Windows.Forms.CheckBox();
        this.chk_option3 = new System.Windows.Forms.CheckBox();
        this.chk_option4 = new System.Windows.Forms.CheckBox();
        this.groupBox1 = new System.Windows.Forms.GroupBox();
        this.button1 = new System.Windows.Forms.Button();
        this.groupBox1.SuspendLayout();
        this.SuspendLayout();
        // 
        // chk_option1
        // 
        this.chk_option1.CheckAlign = System.Drawing.ContentAlignment.MiddleRight;
        this.chk_option1.Location = new System.Drawing.Point(40, 24);
        this.chk_option1.Name = "chk_option1";
        this.chk_option1.Size = new System.Drawing.Size(192, 24);
        this.chk_option1.TabIndex = 0;
        this.chk_option1.Text = "Windows 2000 / Windows XP";
        this.chk_option1.ThreeState = true;
        // 
        // label1
        // 
        this.label1.Location = new System.Drawing.Point(16, 24);
        this.label1.Name = "label1";
        this.label1.Size = new System.Drawing.Size(296, 16);
        this.label1.TabIndex = 1;
        this.label1.Text = "The following products are developed by Microsoft Corp.";
        // 
        // chk_option2
        // 
        this.chk_option2.Location = new System.Drawing.Point(40, 56);
        this.chk_option2.Name = "chk_option2";
        this.chk_option2.Size = new System.Drawing.Size(192, 24);
        this.chk_option2.TabIndex = 0;
        this.chk_option2.Text = "JAVA";
        // 
        // chk_option3
        // 
        this.chk_option3.Appearance = System.Windows.Forms.Appearance.Button;
        this.chk_option3.ImageAlign = System.Drawing.ContentAlignment.MiddleRight;
        this.chk_option3.Location = new System.Drawing.Point(40, 88);
        this.chk_option3.Name = "chk_option3";
        this.chk_option3.Size = new System.Drawing.Size(192, 24);
        this.chk_option3.TabIndex = 0;
        this.chk_option3.Text = "Visual C# and .NET";
        // 
        // chk_option4
        // 
        this.chk_option4.Appearance = System.Windows.Forms.Appearance.Button;
        this.chk_option4.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
        this.chk_option4.Location = new System.Drawing.Point(40, 120);
        this.chk_option4.Name = "chk_option4";
        this.chk_option4.Size = new System.Drawing.Size(192, 24);
        this.chk_option4.TabIndex = 0;
        this.chk_option4.Text = "Oracle Database";
        // 
        // groupBox1
        // 
        this.groupBox1.Controls.AddRange(new System.Windows.Forms.Control[] {
                                          this.chk_option2,
                                          this.chk_option4,
                                          this.chk_option3,
                                          this.chk_option1});
        this.groupBox1.Location = new System.Drawing.Point(16, 56);
        this.groupBox1.Name = "groupBox1";
        this.groupBox1.Size = new System.Drawing.Size(280, 152);
        this.groupBox1.TabIndex = 2;
        this.groupBox1.TabStop = false;
        this.groupBox1.Text = "Select All Correct Options";
        // 
        // button1
        // 
        this.button1.Location = new System.Drawing.Point(16, 216);
        this.button1.Name = "button1";
        this.button1.TabIndex = 3;
        this.button1.Text = "Done ";
        this.button1.Click += new System.EventHandler(this.button1_Click);
        // 
        // Form1
        // 
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
        this.ClientSize = new System.Drawing.Size(328, 253);
        this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                      this.button1,
                                      this.groupBox1,
                                      this.label1});
        this.Name = "Form1";
        this.Text = "Check Boxes";
        this.Load += new System.EventHandler(this.Form1_Load);
        this.groupBox1.ResumeLayout(false);
        this.ResumeLayout(false);
    }
    /// 
    /// The main entry point for the application.
    /// 

    [STAThread]
    static void Main() {
        Application.Run(new Form1());
    }
    private void Form1_Load(object sender, System.EventArgs e) {
        Image imga = Image.FromFile("A.ICO");
        chk_option3.Image = imga;
        chk_option3.ImageAlign = ContentAlignment.MiddleRight;
        chk_option3.BackColor = Color.LightBlue;
        imga = Image.FromFile("B.ICO");
        chk_option4.Image = imga;
        chk_option4.ImageAlign = ContentAlignment.MiddleCenter;
        chk_option4.BackColor = Color.LightBlue;
    }
    private void button1_Click(object sender, System.EventArgs e) {
        string str_opt_selected = "Options Selected are ..\n";
        if (chk_option1.Checked)
            str_opt_selected = str_opt_selected + chk_option1.Text + "\n";
        if (chk_option2.Checked)
            str_opt_selected = str_opt_selected + chk_option2.Text + "\n";
        if (chk_option3.Checked)
            str_opt_selected = str_opt_selected + chk_option3.Text + "\n";
        if (chk_option4.Checked)
            str_opt_selected = str_opt_selected + chk_option4.Text + "\n";
        MessageBox.Show(str_opt_selected, "Checked Options");
    }
}