I've got the latest MBP 13inch with Vista installed on Bootcamp. I've turned the sound all the way up and it's still very low. I've got all the latest boot camp drivers installed, I've tried viewing different videos trying to see if the video was the culprit, but unfortunately it wasn't. I searched around and I've seen others with this issue, but haven't found a fix. I've watched the same videos in Leopard that I did in Vista and they're a lot louder.