Changing the Location Bar Search Engine

Whenever I type something into the location bar on Firefox to try and get it to do a search it takes me a Century Link search engine. I want to set it to use Google as the default location bar search engine, but it won't change. I've changed the preference on the century link engine so that the "Use this as your search engine whenever a 'page not found' error occurs" is disabled, as well as I've gone into about:config and used keyword.URL then changed the value to http://www.google.co.uk/search?q= as well as I've right clicked on the keyword.URL and selected reset, yet my computer still uses Century Link as the default search for the location bar. Does anyone know how can I get Firefox to stop using Century Link as the default Location bar search engine?