The captioning is probably turned on in the source - the boxes. Try to see if there's a toggle that you can turn off at the source.
We've never used closed-captioning before, but our dog-sitter apparently did something either to our Samsung TV or our Tivo box so that the closed-captioning won't go off. When I hit the "caption" button on the Samsung remote, a message comes on that says "Not Available in the Current Mode." I've also tried touching the TV's "Menu" button, and tried the "input," "picture," "sound," and "setup," but haven't been able to find the magic solution. Please help!