I installed
task-pulseaudio, pavucontrol and
padevchooser. And enabled Pulse Audio.
When I try to start pavucontrol, it tells me "Connection failed: Connection refused".
I also tried
qasmixer. It shows
Nuforce as a card with others. When I choose it, the only option I get is the PCM-volume.
Sorry! I really don't have that much experience of soundcards and their configurations!

I disabled on board sound card in BIOS, but unfortunately it didn't help either.