i really don't know what caused the problem. My browser cant anymore play sounds/music, like in youtube. i can see it playing. but there's no sound. During the my windows startup, there's nto starup sound anymore. I tried using other browser like firefox, no effect. i've downloaded the shockwave player and the latest flash player still no effect. But when i try to play music from media player, and itunes. it played. Seems it can't play system sounds anymore.Anybody here who could help me please.