I don't know if this will help, but you can try it. I believe the problem is caused by your game settings, not Win 7
It is caused when a sound setting is set too low in the game parameters. Go to the game options and go to the audio and grab both volume sliders and center them, then exit options. When you next run the game, you must set your sound volume so it is comfortable. If this problem returns the next time you run the game, your config.cfg file might be set to "read-only" or you might have the offending settings in your userconfig.cfg file. You must make the file writable, fix the problem, then set it back to read-only when you are done. If the settings are in your userconfig.cfg file then you must manually go and delete the setting.