A newly purchased dvd plays on my laptop and old Panasonic vhs/dvd player, but not on the much younger Sony dvd player on the Home Theatre system connected to my main TV. Other video dvds play fine on the Sony.
There are no updates for the Sony online.
Can anyone suggest why this should be, and if there is a solution, as the Sony is connected to a larger TV in our main living room rather than an upstairs room with a smaller tv?
The DVD may have a different region code than the Sony HTS is authorized for.
The way the DVD is mastered can affect if it plays or not. Since you can't change the Sony HTS firmware then connect your laptop or DVD/VHS to your living room TV when you want to play it.