Several months ago the web site Istarthere hijacked my home page.

I got rid of it. Or so I thought.

Now I find that if I click on the Search function on my hme page then Istarthere comes up there.

Also, I found out that its still there when I click on the DEFAULT
setting when I am trying to change my home page setting.

What can I do to completely eradicate this pervasive pest?