GUI Windows Form C#

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Diagnostics;
public class Form1 : System.Windows.Forms.Form {
    private System.Windows.Forms.RichTextBox richTextBox1;
    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.Button button2;
    private System.Windows.Forms.Button button3;
    public Form1() {
        this.richTextBox1 = new System.Windows.Forms.RichTextBox();
        this.button1 = new System.Windows.Forms.Button();
        this.button2 = new System.Windows.Forms.Button();
        this.button3 = new System.Windows.Forms.Button();
        this.SuspendLayout();
        this.richTextBox1.Location = new System.Drawing.Point(8, 8);
        this.richTextBox1.Name = "richTextBox1";
        this.richTextBox1.Size = new System.Drawing.Size(272, 232);
        this.richTextBox1.TabIndex = 0;
        this.richTextBox1.Text = "";
        this.richTextBox1.LinkClicked += new System.Windows.Forms.LinkClickedEventHandler(this.richTextBox1_LinkClicked);
        this.button1.Location = new System.Drawing.Point(24, 256);
        this.button1.Text = "Zoom Out";
        this.button1.Click += new System.EventHandler(this.button1_Click);
        // 
        this.button2.Location = new System.Drawing.Point(192, 256);
        this.button2.Text = "Zoom In";
        this.button2.Click += new System.EventHandler(this.button2_Click);
        // 
        this.button3.Location = new System.Drawing.Point(112, 296);
        this.button3.Text = "Normal";
        this.button3.Click += new System.EventHandler(this.button3_Click);
        // 
        this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
        this.ClientSize = new System.Drawing.Size(292, 333);
        this.Controls.AddRange(new System.Windows.Forms.Control[] {
this.button3,
this.button2,
this.button1,
this.richTextBox1});
        this.Text = "RichTextBox Zooming";
        this.ResumeLayout(false);
    }
    [STAThread]
    static void Main() {
        Application.Run(new Form1());
    }
    private void button1_Click(object sender, System.EventArgs e) {
        float zoom = richTextBox1.ZoomFactor;
        if (zoom / 2 > 0.015625)
            richTextBox1.ZoomFactor = zoom / 2;
    }
    private void button2_Click(object sender, System.EventArgs e) {
        float zoom = richTextBox1.ZoomFactor;
        if (zoom * 2 < 64)
            richTextBox1.ZoomFactor = zoom * 2;
    }
    private void button3_Click(object sender, System.EventArgs e) {
        richTextBox1.ZoomFactor = 1f;
    }
    private void richTextBox1_LinkClicked(object sender, System.Windows.Forms.LinkClickedEventArgs e) {
        Process p = new Process();
        p.StartInfo.FileName = "C:\\Program Files\\Internet Explorer\\IEXPLORE.EXE";
        p.StartInfo.Arguments = e.LinkText;
        p.Start();
    }
}