https://developer.mozilla.org/devnews/index.php/2009/07/16/firefox-3-5-1-update-is-now-available-for-download/
Get it here...
http://www.mozilla.com/
Local Link = ftp://ftp.is.co.za/pub/mozilla/firefox/releases/3.5.1/win32/en-US/Firefox%20Setup%203.5.1.exe