sound for BF942

[lucky luke15]

ok guys i'm stumped??? I installed bf 1942 and my sound when loading cuts in and out. when i play the game sound works fine. But my dad also plays and his sound is speed up like every thing is 5 time faster that what it should be. any help with my problem would be great!!! we have the same sound card i think but our problems are no the same. thanks

my pc:
xp1700
700+ in ddr ram
geforce 4 ti4400
sound baster

Dads pc:
850 althon
geforce 2 mx 400 (64mb)
256 sd ram
sound blaster