My search engin- google- has been hijacked.

A business website has highjacked my search engine. In options Google is set as my default search engine. When I click the Google icon in the task bar all I can get is Yahoo. Yahoo is not set in options as default or alternate search engines. How can I get rid of it?
Thanks, Richard

Excuse me. It’s the Firefox icon I use. Results are as described.

Try run Malwarebytes Adwcleaner >> https://www.malwarebytes.com/adwcleaner/