The darn TV should pop into Video 1 when she turns on the DVD player. She says she had it hooked up to something else and it worked fine. But yes... DVD players can go bad quickly. I've had a few that worked for only a couple of hours and had to be returned because they stopped working.
I've been skimming manuals. If works good on another set then it should work on this T.V. just fine. Not all T.V. pop into Vid 1 automatically, that is why I was trying to find out what model of Sony it was.

We have a three year old Sony and ours never pops right into a video mode. We have to press the tv/video button on the front of the tv to either video 1, video 2 or video 3.