Please Help!! Asus K7V onboard sound is horrible!!

[Ash654]

I have an Asus K7V MB and use the onboard AC97 sound. It worked fine at first but suddenly started to crackle and sound scratchy. Sometimes after the system has been shut down for a while it worked fine but shortly after it became crackly again. Lately it's just been crackly without clearing up for a second. I have tested the speakers and they work perfectly so that's not the problem. Any help would be greatly appreciated.