dont hear sound effects

Everytime when i play gw i only hear the music from the towns and outpost and never hear the effects of skills and when i get to an cinematic some time i hear one or two lines after that it stays mute can any 1 help me may b my sound card

It had gotten messed up by Anet just sometime during the time frame of NightFall patch. They have fixed a few so far.

I still notice sounds missing, for example Arbostone, the person carrying the urn - when they get hit, the shield sound FX is missing.