please install the search reset addon - it will revert the some common customizations that adware programs do in firefox back to the default: https://addons.mozilla.org/firefox/addon/searchreset/ you might also want to run a full scan of your system with different security tools like the [http://www.malwarebytes.org/products/malwarebytes_free free version of malwarebytes] & [http://www.bleepingcomputer.com/download/adwcleaner/ adwcleaner], which are specialised in adware and browser hijackers. [[Troubleshoot Firefox issues caused by malware]]