Going off memory (and that's failing)
Thing the first
1: Check it's not muted !!
2: Go into Hardware manager/system and see if there's a yellow question mark anywhere but particularly next to audio device as this would signify that the sound drivers have not been re-installed.
They are usually on the motherboard Resource disk but it doesn't matter if that's gone AWOL as you could download the correct/newer drivers from the manufacturers website.