Chrome users
You can also temporarily turn off an extension by disabling it on the Extensions page:
Your browser Homepage/Start page still not restored to your previous selection?
Google Chrome allows you to change the browser default search provider at any time. Click on the wrench icon in the upper right corner of the the Google Chrome browser and then click on "Settings" from the drop down menu. In the Settings window, use the drop down menu in the 'Search' section of the page to select your desired search provider.
Safari users
You can also temporarily turn off an extension by disabling it on the Extensions page: