I hate to say it, but I've had this prob before as well, and the only thing that *might* fix it is changing drivers. If you don't have the latest driverrs for the ac97, get them. If you have them already, and are having this prob, try rolling back to an older version of the drivers. The same is true with directX, but don't roll back the version of directX, leave it alone. Imagine that each sound in the game is given a sound channel. The ac97 tends to "lose" a couple of those channels sometimes. Guns are the most noticable, but there are a couple other sounds that get muted, if I remember correctly. Also, make sure you don't have any other apps running in the background... messengers like yahoo and msn can try to steal the focus of windows, and potentially screw something up.