1. Tell me about the version of motherboard chipset drivers. Be specific. I can't in this discussion since the machine under discussion has no make or model.
2. Try the old DMA flip noted at http://winhlp.com/node/10 since this can cause crackling noise.
And finally, could it be the speakers?
A few months ago my computer got hacked and then completely crashed. I had to completely reimstall WindowsXP. Everything has been working properly except for the sound. I reinstalled all the drivers and even purchased a new sound card and installed updated drivers for that. Nothing seems to be working. I have also tried different speakers to see if that may be the problem. Any suggestions would be much appreciated. Thanks