I'm used to search in google by typing keywords to my address bar. Now for some reason every word I'm typing is tried to interprete as a website. It is similar to google's "I'm feeling lucky" option, but with the difference that I can only type one word and only if it is writte correctly. Typing stackoverflow directed me to stackoverflow.com but rtackoverflow led to an error page.
In older versions we would enter about:config and change the value of keyword.URL.
I've already read that keyword.URL has no functionality anymore but this can be undone by installing FireFox - Addons like keyword.URL-HACK. That did not work, because I don't have any keyword.URL in about:config!