When play no sound...

[Wil25000]

Hi there,My computer is much better.But when I play the sims 2,There is no sound.Then I'm try play music with winamp is working.What happen with my computer?need re-format the computer?All Sound setting sim 2 already into max.
Here my new :new: spec:
Vista Ultimate
Realtek sound ac97
Intel Core 2 Duo
Geforce 7200
2GB Ram
Thanks if you Guys want help me... :(