my system was reding a dvd a day before, but its not recognizing it at all?

Question

why it is that the dvd is running nicely in another pc but not in my pc

the dvd was running nicely yesterday on my lap top, but today my lap top is not recognizing in the same .
it was also recognized and run nicely in my sisters computer, ev ery day what is the problem with my system

Answer 1

May not be compatible with your DVD player (i.e dual layer DVD trying to play in a single layer DVD player)