ok, have you done the SP1 upgrade, and have you done the XP processor patch for the AMD chip?? Make sure you have the latest Gforce4 drivers..you oculd also try installing
WinAmp3 This may work, it's an MP3 player and pretty good, will play almost any file, this could sort the MP3 codec warning. If this doesn't work i will have to look a little more into it.