No speach when playing a dvd

Could anyone help me with the following problem: Just installed a Pc with Windows XP home Edition. Pc is Installed with a brandnew motherboard Asus
A7N8X-X socket A with AMD-2600 processor. Videocard :Asus V999LE (Geforce 6800 LE 128 MB). Problem is: When i play a DVD The music of the picture can be heard loud and clear, but when people are talking you can hear all sounds BUT the talking. Can anybody tell me whats wrong?

Why have you posted this a second time when your original thread is still active: