Hi there, same probleme here.

XP Pro system (not SP1, the original release)

1,43 Ghz AMD CPU
390 MB SDRAM pc133
SB Live! sound card (and a AC97 integrated one too)
Nvidia Gefroce MX 200 64 MB DDR
I tried with and without a clean boot (nothing loaded expet windows core, sound card driver, graphic card driver) and both sound cards.

I have exactly the same ****ing probleme than you.

I've tried to update and unupdate drivers
I've uninstall ALL codecs and réinstalled the one of freelancer spécific.

Nothing does.. Still have problemes with some sounds not always playing while other sounds playing.

Help us !

Well.. this isnt really a fix.. but I just turned the sound effects off.. and it plays *decently* anyway.. you get all the vital info from ship voicing and music.. weird thing is that there´s no sound in some cutscenes without MUSIC turned on, and still some are missing.. dunno if they´d have worked with sFx anyway.. I actually think I had this problem with Privateer (!!!!) too, so it´s r e a l l y old.. only two games it has ever happened to, and on totally different comps.. well.. in reality there´s no sound in space anyway, so.. But God knows I´ll be dling an eventual expansion off Direct Connect if they keep putting out half finished and buggy releases like this.. I´m not gonna pay for two games to get a half-working version of the one I payed for in the first place.. *there´s not even escort missions..* sheeesh.. gl to you