How to reinstall sound?

I'm not even sure if sound was working after the install, I have installed things and 'apt-get upgrade' since then.

When I realized I had no sound, I tried installing 'emu10k1' from this list: http://www.alsa-project.org/main/index.php/Matrix:Vendor-Creative_Labs

But it didn't work, or maybe I made a mistake.

I think I should let Ubuntu autodetect sound and reinstall it, to see what happens, but how do I do that?

Any other info is greatly appreciated.

Note: I'm on Ubuntu 12, as host. My sound card is "SoundBlaster Live! 5.1"

Note 2: I've been using linux for some time but only as VM's. I'm moving from windows 7.