No sound when playing dvd's

I just installed a new XP Home OS, a new hard drive and am using pre-existing CD Rom drive and a HP DVD-rw drive. The CD drive plays audio ok. The DVD rw drive plays cd audio ok. It also plays dvd video Ok but there is no sound from the dvd-rw drive when playing videos. Tried checking codecs. all seem ok. Tried Power DVD player - no sound. Windows media player 11 installed, still no sound. Installed DIVx player...no sound...what could be the problem? Remember the DVD-rw drive plays audio cd's with great sound. I'm lost.

 

Hi, I bought a DVD burner for my older PC and installed it and it worked OK , burnt DVD's and CD's Ok , but when I played a DVD there was no sound, the burner came with Nero 7 and I installed that but still no sound on DVD , CD sound was great,
So I checked around , my wifes PC came with Power DVD disc , so I installed that and it all works great, the sound now works in Media Player as well,
As hers only has a DVD Rom , I dont have a disc for NTV DVD & CD Burner 7 which is on my laptop, it seems a lot better burner than Nero 6 or 7.
Just what I found . Cheers Des.