how can I change the search results coming up when I enter a term in my address bar from through yahoo to through google?

when I used to enter a term in my address bar, search results through google used to come up; suddenly, I'm getting results from yahoo! I want results to come through google. I've cleared my add-ons and set google as my home page, yet it persists; how can I make it search through google? p.s. I know I can search through google by entering the term in the "search engine" area to the right of the address bar; I want to know how I can do so straight from the address bar!

Thanks!