Computer audio problems after installment of graphics card?

ive just installed a new graphics card and i tryd to listen to some music and no sound was coming from the speakers i have i check all my wires and the correct plug-ins im not that big on computers but when i mouse over the uhhh speaker on the desktop it says digital output device HDMI idon'tt have hdmi output is there a way i can change it back to what i recently had?