use cpu-z...read your mb model and vendor info...google it and download the soundcard drivers. when sound comes back the go to sound chipset vendor and download the newer drivers. if there no sound check that the speakers are in the right port on the back/front header. (play an audio cd or mp3 file.). on most soundcard if there colored ports it the green one. check in the bios that the onboard soundcard i turned on. check in windows that no one mutted the sound.