Every once in a while, the volume on my mp3s goes up and down quickly. It is not an issue with an individual mp3 file. I have replaced the sound card, but the new one is also starting to do it. The original, a Soundblaster Live card, got to the point where I couldn't listen to anything without eventually waking people up. The Audigy 2 card isn't as bad, yet. I am using a new harddrive and am still having issues (both cards ran on XPpro). The programs in question are Windows Media Player and Winamp.