Site unblock

Question

hello

how to unblock website using c#

i have block code 

String path = @"C:\Windows\System32\drivers\etc\hosts";

StreamWriter sw = new StreamWriter(path, true);

String sitetoblock = "\n 127.0.0.1 " + textBox1.Text;

sw.Write(sitetoblock);

sw.Close();

lblStat.Text = textBox1.Text + " site Blocked";