I never use such a thing. I look at my machine and then head to the maker of my computer or motherboard.

In XP however the most common cause I encounter for crackling is the old XP DMA BUG. This was NEVER resolved by MSFT and the fix is easy, required no install or reboot. Try it now at http://winhlp.com/node/10

Some don't want to do this or want a long explainer. Sorry but it's a very common issue worth about 3 minutes and it's gone. Why go any deeper?