Very weird problem when watching dvds

i wasnt exactly sure where to post this but anyway here goes. i went to watch a dvd on my pc yesterday and as i started to watch i realised that there was no actors speech. there is the movie music and background noise and such but no sound coming from any of the actors.i uninstalled and reinstalled all my codecs but that didnt fix it, i uninstalled and reinstalled my dvd drive but that didnt fix it either so now i come to the people of techspot looking for a solution.if anyone has any ideas your help if greatly appriciated.

cheers

EDIT: i also downloaded a movie off the net and it worked fine.

Sounds like you have a 2 channel speaker setup and the DVD is playing in 5 channels.

i have 5.1ch speakers but for some reason in my sound options it was set to 2 speaker setup.i set it to 6 and i get speech now but its very muffled but if i set it to 4 speakers its perfect.im beginning to think maybe its an error with my sound driver.i thank you very much for your extremely simple solution, i feel like a retard now for not thinking of it myself lol