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 public static string getDefaultBrowser()
        {
            string browser = string.Empty;
            RegistryKey key = null;
            try
            {
                key = Registry.ClassesRoot.OpenSubKey(@"HTTP\shell\open\command", false);
                browser = key.GetValue(null).ToString().ToLower().Replace("\"", "");
                if (!browser.EndsWith("exe"))
                {
                    browser = browser.Substring(0, browser.LastIndexOf(".exe") + 4);
                }
            }
            finally
            {
                if (key != null)
                {
                    key.Close();
                }
            }
            return browser;
        }