In this order:
Turn mute off.
Make sure your speakers are plugged in.
Make sure your speakers are turned on.
Make sure in-game volume settings are turned on/up.
Make sure your sound card is compatible with Sins.
Make sure your sound card driver is up to date.
Make sure the sound files have been installed properly (happened to me once on another game, the game installed but the sound files were left behind).
Re-install the game.
Contact [email protected] if all else fails.
Good Luck!
