I am having a big problem playing dvds. none of the applications work. with some of them i can hear the sound but no image. noone has been able to find the solution. This message appears when I try to play a dvd:” The DVD navigator was not detected. If you don't have one installed, you will need to upgrade your system. Otherwise, try to reinstall your DVD Navigator.” Please, if you know the solution to this problem, I would really appreciate your help. thank you!