Yesterday I purchased S.O.G. Prairie Fire, and after the long wait downloading it I started up the game. I made sure I didn't run any mods. Also I unloaded Global Mobilization before launch. When the game launched, I could hear sound in the main menu. Specifically the background music and ambient noises. Also I could hear the clicking when pressing a button. Even after selecting the campaign I could still hear these sounds. Once I got into the briefing of the first mission, I stopped hearing any sound. Once the first mission loaded, I still wasn't able to hear any sound. The settings didn't change.