Try setting the bios to enable on board sound.
As there is no make or model, I'll keep the replies very short.
i have a desktop pc with a built in sound card (that had an another sound card in it that i removed), i installed ubuntu and everything works fin except for the built in sound card, i don't know what is the solution, can anyone help, is it because i removed the other sound card (is there a jumper or something i should reposition in the mother-bored?)
or is it a software problem??