How to open a web browser using C#

How to open a  web browser using  C#

using System;

using System.IO;

using System.Net;

using System.Diagnostics;

using System.Windows.Forms;

namespace WindowsFormsApplication1

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click_1(object sender, EventArgs e)

        {

            webBrowser1.Navigate(textBox1.Text );

        }

        private void button2_Click(object sender, EventArgs e)

        {

            String source = ("viewsource.txt");

            StreamWriter writer = File.CreateText(source);

            writer.Write(webBrowser1.DocumentText);

            writer.Close();

            Process.Start("notepad.exe", source);

        }

    }

}