Just a suggestion but really not sure it will fix you problem :
If you have an onboard Realtek chipset for sound , try to update it with the latest drivers available, realtek and punkbuster often cause what you describe there, a little google search with terms " realtek punkbuster " will maybe find you some tips or solutions, at least it will bring you many other similar problems with PB and various games, some fixed the problem by adding a dedicated small soundcard, also you can try to disable in windows device manager the sound chipset for testing purpose, not just putting windows sound to level zero, but disabling it completely, or directly disable it in the BIOS if you are comfortable with such things, then try to play a bit without sound and see if the crashes still happen to confirm the probable Realtek issue.
That's all i can think about for now.