I have a P4 2.60c, 256 MB DDR RAM and Windows XP SP2. The problem is that I don't get any sound (only video) while playing dvds on my PC. I have a Samsung SD-616Q DVD ROM Drive. I have tried PowerDVD & RealOne player to no avail. Windows Media Player doesn't even play the DVDs. But these DVDs play fine on my DVD player (for the TV). Please help.