sound goes slomo?

hello. Recently, my computer started doing something wierd. Whenever I play a game such as counterstrike, the sound will go low and be in slow mo…however, if i listen to music, then it plays normally. anybody know how to fix this problem?
I am running:
Winxp pro
VIA chipset FIC Az-11 motherboard
amd athlon 800 mhz
I believe that it is something to do with the drivers, because i recently installed the winxp…and nothing else changed but that so it leads me to believe that windows for some reason copied an inferior driver over my previous one…i went to the FIC website and d/led the correct driver, but the problem still persists.