Heather's problem apparently is that her DVD player or TV is cropping the ends off so the entire picture fills the screen, thus cutting off part of the movie on the sides.
There could be a couple of possible issues here.
The TV could be set to display the picture in the wrong aspect ratio. Heather said she has newer HDTVs, which leads me to believe that they are widescreen LCD or plasma sets.
If so, it's possible that each TV is set to display movies in the wrong aspect ratio, or the relationship of the screen's width to its height. All televisions have a setting in which you can set it for different screen shapes, or you can zoom in on the picture. If you're watching an older show in a 4-by-3 or more squared aspect ratio on a widescreen TV, you can zoom in so the image fills the entire screen. But if Heather is watching a movie that has a wider aspect ratio than her TV, the image could be zoomed in, which explains why the credits are cut off on the sides.
The DVD player could also be the culprit. Set top players for televisions, whether they be cable or satellite receivers, DVD or Blu-ray players, or DVRs, have the same kinds of settings for a television's aspect ratio. Check to make sure those are set correctly.
Another slight possibility is the TVs are overscanning the picture area. "Overscan" refers to the extra picture area around the edges of a video image that are cut off by the TV.
The older cathrode ray and rear-projection TVs were especially guilty of overscanning because TV manufacturers wanted to make sure a broadcaster's video image was completely covered in a TV screen.
Newer LCD and plasma TVs, however, don't really suffer from overscanning because they're supposed to be mapped exactly from edge to edge as the broadcaster's image. But there could be a slight issue with the new TVs. That is perhaps something you should check with your TV manufacturer.
If you have a tech question for Vince, email him at firstname.lastname@example.org, and he'll try to answer it for his column in The Salt Lake Tribune or on its website. For an archive of past columns, go to www.sltrib.com/topics/ohmytech.