HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(txtUrl.Text);
req.KeepAlive = false;
HttpWebResponse res = (HttpWebResponse)req.GetResponse();
StreamReader sr = new StreamReader(res.GetResponseStream(), Encoding.Default);
StringBuilder sb = new StringBuilder();
String strFilePath = @"e:\doc\" + DateTime.Now.ToString("MMddHHmmssfffff") + ".doc";
System.IO.StreamWriter sw = new System.IO.StreamWriter(strFilePath, false, System.Text.Encoding.GetEncoding("gb2312"));
while (sr.Peek() != -1)
    sw.WriteLine(sr.ReadLine());
sw.Close();

System.Diagnostics.Process.Start(strFilePath);