I got full source code using URL and I removed all image tag using regular expression now I need to remove all type of video file using regular expression .
coding:

WebClient wb = new WebClient();
string storeDate;
storeDate = wb.DownloadString(textBox1.Text);
MessageBox.Show(storeDate);
string result4 = Regex.Replace(storeDate, @"]*>(?:\s*?)?", "", RegexOptions.IgnoreCase);
MessageBox.Show(result4);