Drivers were reinstalled-speakers won't work.?

I had my computer fixed recently, and it runs great, but for some reason the speakers will not work. Apparently they reinstalled all the drivers, and told us that the audio driver was on there, so we'd have to get help elsewhere, it must be the machine. I have a Dell PC, 8400 with 5.1 surround sound speakers. I've tried to reinstall a few of the programs that were previously on there and use updates from dells website, but i still have no sound. If anyone could direct me to the proper updates, and/or instructions for new installation, that would be awesome. I do or at least did have sound blaster Audigy 2 zs, which i've tried to reinstall off the disc and uninstall a few times.