Annoying sound Problem

hi there i have just installed vista great programme but as soon as i did all
my sound died not even a crackle after looking for my drivers i gave up and
brought a usb sound card. on audio set up screen it shows sound is being
ouputted the green bars but nouthing through the speakers or the headphones i
tried. i noticed i can adjust the line in and mic volume but not the speaker
volume in the levels settings


please help