How to block pop-up in C# win form?

I have a form.It have 1 textbox, 1 button, 1 webbrowser
the code is following

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void buttonGO_Click(object sender, EventArgs e)
        {
            webBrowser1.Navigate(textbox.Text);
        }
    }
}

When ever i open any website it opens well and it works.
But the problem is that it cannot block pop-up from any site.
so anybody plz give me a code for blocking pop-up and i am new to C#.so plz tell me step by step.

thanx in advance.