Sound compression coming from Windows XP?

I'm running audio into a soundboard from a Dell XPS 400 Windows XP unit. I've got the computer run into a Direct Box made specifically for PC audio. It runs in by 1/8" connection, and out of the direct box by XLR straight into the board. For some reason, the audio coming in to the board is heavily compressed, and I'm trying to figure out if it's the Direct Box or the computer. Has anyone else had problems with Windows XP heavily compressing output audio?