Tv out will not stay in widescreen

Anyone else run into this, when I play a movie, widescreen movies, and using
the TV out so I can watch it on the television, the movie starts out fine
then switches from widescreen to fullscreen after about a min. or two.The
movie on the comp. monitor is still in widescreen but the TV is not. This
prob just started recently, it happens no matter which player I use,
(Zoomplayer, BS player, Windows Media etc). I can change the aspect ratio on
the players which results in the movie aspect changing on the comp. monitor,
but no effect on the TV. I have an Nvidia card installed on my machine.
Thanks