Computer Sound drivers..

Hello everyone,

I had to re-format my computer to get it to work again, and re-install windows, but now I have absolutely no sound! My computer makes a sort of internal beep whenever I get an error screen, which.. I think means my drivers aren't installed; and is highly annoying. I ran a program to see what kind of motherboard I have, and.. It said 'unknown'.. I got my computer from a friend, and It's really weird.. Sort of looks like it's from Japan and has headlights, haha! But anyways.. I really have no idea what to do.. I'm only relatively able with computers, I'm not a professional or anything, and I could really use some advise.. Thank you if you are willing to provide some. :)

Sincerely,

-Lacey