I saw that many people asked this question but it just does not work for me!
try
{                      
    ProcessStartInfo startInfo = new ProcessStartInfo();
    startInfo.FileName = @"C:\Program Files\Internet Explorer\iexplore.exe";
    startInfo.Arguments = Url.ToString();
    startInfo.CreateNoWindow = true;
    startInfo.ErrorDialog = false;
    startInfo.UseShellExecute = false;
    startInfo.WindowStyle = ProcessWindowStyle.Hidden;
    Process.Start(startInfo);
}
catch (Win32Exception ex)
{
    var err = ex.ToString();
}
It still opens the browser ! anybody can say why?