No Sound on New Build

I just finished getting my first self built computer together. I installed xp, and after solving a few problems, im left with just one. I have no sound. There is 6 channel audio on my asus p5q board, and a headphone header and a mic header. Im running windows xp with SP3, (originally i had no service packs, which lead to one of the problems i posted on this forum yesterday, but i got it fixed). There is a sound picture thing in the bottom right, and i can adjust the volume, but still get no sound. In device manager, there are no yellow question mark things, because i installed all the drivers. Device manager says all of the audio things are working fine, so i don't understand why i am getting no sound. Any suggestions? Thanks to everyone who helps.

thnx for trying to help, but this is pointless now. My comp is dead, i get a bunch of b's across the screen with blue lines, i think its the video card. I tried to clean install but there still there. Im getting really sick of all these issues, this is the 5th or 6th issue ive had with this comp after getting it built. I think im just gonna take it to the shop and tell them fix it, ill pay for whatever, just get the thing running perfectly.