It's probably set as your default search engine. You can change it to something else like google or bing. In internet explorer open the Manage add-ons and then Search Providers. In firefox you can click on the down arrow that's next to the search engine logo in the search box and goto Manage Searc Engines, the one on top is the default. I don't use chrome so if that's what you use, there should be a way to change it for chrome too.