Here's the other thread
It might offer some thoughts or places to look. You need to, as best you can, isolate this to either your PC or speaker system first. This poster said the volume of the sound was independent of his speaker controls. To me, this suggests something in the speaker system and not the PC because that signal is what's amplified by the speaker's electronics. Can you tell whether you can turn these sounds up and down using the PC's or speaker system's volume control? Can you try another set of speakers on your PC or connect the speakers to another device? I believe there was a thread on this topic where it did come down to the speaker system. I'm still skeptical of the Real Player notion, BTW, but sometimes using logic doesn't always work.