slow-mo games and sound

hello all!

if anyone could offer some advice on the following problem id be most grateful!

i recently replaced the motherboard in my pc and since then its having the strangest problems, in games the sound is metallic and slurred, games like modern warfare and even black and white 2 play in slow motion, and i mean smooth, high fps slow-mo! the sound is horrible too. But somehow oblivion, plays beautifully, the motherboard is better and the ram is better and the settings havent been changed in any game, even running the games in 640x480 doesnt change it!

i have :
core 2 duo 2.3
2gb ram
g41m-p36 msi motherboard
asus 9600gt mg
sound blaster 24bit 5.1
2x sata seagate hdd
windows xp

the old board was an intel dg33bu

i have formatted, put only the latest drivers for all components on and still the problems persist! please help!