System.Net's Webclient in C# won't connect to server

using System;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Net;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            using (WebClient client = new WebClient()) {
                string s = client.DownloadString("http://www.google.com");
                this.textBox1.Text = s;
            }
        }
    }
}

Updated proxy settings
Current WinHTTP proxy settings under:
  HKEY_LOCAL_MACHINE
    SOFTWAREMicrosoftWindowsCurrentVersionInternet SettingsConnections
      WinHttpSettings :

 Direct access (no proxy server).

using (WebClient client = new WebClient()) {
            string s = client.DownloadString("http://www.google.com");
            // do something with s
        }