Screen size adjustment

Question

We went on vacation and the house sitters did something to the TV! The HD channels used to show letterbox style from which we could zoom in through the 'wide' button on the remote. Now the screen is stuck at the normal square size, and cuts off the edges of HD programming, without the bars on the top and bottom that allow for the zoom feature. I've messed about in the 'picture menu' from the TV remote to no avail...Can anyone tell me how to remedy my television's affliction?April