I just refered somebody else to this, I never really looked in the X-Wing/Tie Fighter section before so sorry if I'm late.
First you'll want to go to Yoda's Help Desk on Lucasarts.com. (http://yodashelpdesk.lucasarts.com/
Next, under 'All Games' pick Star Wars: TIE Fighter. It may take a while to load, so don't worry if its going slow. It will load eventually. After that, click on Windows XP. Then go down to All FAQs on the drop bar. There are a few questions related to sound and music, they may help. If not, just go to 'Email Tech Support' and ask them. They usually know.
Hope you subscribed to this topic, most people do for support questions.