Motherboard Sound Problem.

Hi I'm Having Trouble With My Motherboard Sound.... Every Time I Run A Game Program I Cant Seem To Hear Anything... I Check The Option In The Game Its Fine... And Just To Make Sure Its Not Just My Game I Even Reinstall It And Still Have The Same Problem... I Don't Understand Why Its Doing This... But All I Know Is That Audio/Sound Don't Work While Game Playing... I Try Like 20 Other Games And Still Same Problem.... And I Even Did Update on Vista... But The Thing Is... When I Updated My Windows Then That Where I Start To Have These Problems.... I Even Reinstall Windows And Try Not To Update It But I Don't Know I Still Keep On Having The Same Problem.... Can Any 1 Help Me Out?

Microsoft Windows Vista Ultimate

System Manufacturer ECS

Processor Intel(R) Core(TM)2 CPU 6300 @ 1.86GHz, 1862 Mhz, 2 Core(s), 2 Logical Processor(s)

Delta DC-770 On NVIDIA GeForce FX 5900XT