what dvd decoder are you using? You may want to update it. I use PowerDVD i dont think it really matters but they may have a fix if it can't decode your new dvds
No I think as long as you have the MPEG-2 codec installed the program is insignificant, but installing WinDVD/PowerDVD provides the codec, but after then it should be playable on WMP etc...
hmm wierd, before i had sound with those and i didnt install windvd or powerdvd and now when i dont have sound i install those two and i have sound again. must be those codec packs overwritten some files.