It is possible that your anti-virus software is corrupting the downloaded files or otherwise interfering with downloading files by Firefox.<br /> Try to disable the real-time (live) scanning of files in your anti-virus software temporarily to see if that makes downloading work. See "Disable virus scanning in Firefox preferences - Windows" *http://kb.mozillazine.org/Unable_to_save_or_download_files ---- You can find the latest Firefox release in all languages and for all Operating Systems here: *Firefox 12.0.x: http://www.mozilla.org/en-US/firefox/all.html Download and save the Firefox installer to the desktop and start the installation with a double-click after you've closed Firefox.