Ubuntu Sound Issues

Dear Macrumors,
After a failed attempt at reinstalling windows 7 on my friends computer (Dell Optiplex 760), we decided to load Ubuntu on it. Hes loving Ubuntu and all, but theres one issue, no sound. Now his computer had problems with sound back when it was still on XP, so its not a ubuntu thing. Knowing that, we decided to go to the computer market, and we got this USB-Sound Port thing, and it works on my laptop. We had to get my Win7 Laptop to play off the USB, and not the laptops own speakers.
So i was wondering, since its not working in Ubuntu but it worked on my laptop once i made my laptop recognize it, i was wondering if that would be the solution to my friends sound problems, and if im right, how could i go about doing this?
Just a recall, my friend bought a USB to Sound port, it works, its just not working on his computer, how can i solve this?
We are both pretty much noobs, so an idiot-proof version, if you can come up with any solution at all, would be GREATLY appreciated.
Again, thank you in advance,

cheers,
AJ--