Civ4 Complete no sound except wonder animations

[guspasho]

Hi. For some reason that I can't determine, I get no sound from Civ4 Complete except for the 2K Games/nVidia/Firaxis video logos that appear when you load the game and the wonder animations. Those two things sound fine but everything else is missing. No sound effects, no music, no Leonard Nimoy. All the sound settings in the in-game options are set to enable everything but I still get nothing (except the wonder animation sounds). I've tried checking and unchecking the "No sound" boxes but to no effect. What else can I do? TIA