It keeps changing to mp3toolbarsearch (powered by Yahoo) Here are some of the things I've already tried: * Deleted the user.js file * Deleted the prefs.js file * Uninstalled Firefox (including preferences etc.) then reinstalled * System restored Windows to a date before the problem started * Scanned using many, many anti spyware, anti virus software Update: Just found out this problem is cross-browser. My homepage is now changed to MP3search on IE and Chrome.