I've already used the search engine and the results I found were similar but not the exact same thing.
In the beginning I had absolutely NO sound at all but then I downloaded some DirectX thingy and now the only thing I hear is background music and voices.
The gameplay is extremely boring with lacking footsteps and ambient noise.

I'm on windows XP so I can't change the sound quality. I've tried to upgrade the audio driver, reinstall the game as well as changing the sound to 5.1.
All, of course, to no avail.
My motherboard is Gigabyte and my onboard audio "card" is Realtek, which is said to cause the problem but since it's onboard, I can't do anything about it.

Do any of you happen to have the solution?
Thanks.