After i boot up my computer, i can listen to music, play games all fine. But after a while, it just stops. I get an error in wmp, no audio in games, cant watch movies. I have to restart my computer to get the sound back. What might be the problem? 
Motherboard: Asus Rampage II Extreme
Sound Card: SupremeFX X-Fi
Thanks!

Motherboard: Asus Rampage II Extreme
Sound Card: SupremeFX X-Fi
Thanks!