Yahoo toolbar can be removed. There's a Google search bar, too. I've been "offered" that a few times and rejected it. I've got a Google icon on the Firefox toolbar and use that when I need it.
Be very careful of things that install McAfee when you aren't watching. That takes serious effort to remove again.
And once you have AOL, the only way out is to wipe and start again. I spent an afternoon last week with my clerical boss trying to remove AOL from a laptop. We thought we'd won, and lo! It was back - in a folder where we'd deleted it an hour or so before.
Mind you, McAfee was on there too - provided by AOL.