I bought a dvd box set (2 dvds) from an Amazon seller. The first one played fine on my dvd player/tv but the second one wouldn't. I put it in my laptop and it played fine - why is that? They offered me my money back but they haven't got another - and it is quite hard to find and rather expensive when you do, so I have decided to keep it as at least I can watch it on something. Is there anything I can do with the dvd which would make it play on my Sony dvd player?