Whenever I search the Internet lets say yahoo a different search engine comes up or a advertisements?

Question

How do I stop it from doing this

Answer 1

It sounds like you have spyware. Download Spybot Search & Destroy. It's free and run a bot check and delete any spyware that comes up. See if that helps. Also, check in your control panel under programs and see if the search engine is listed. If it is deleted it from there.