I installed Ubuntu to my IBM ThinkPad during last weekend. Everything else went smooth but for some reason sounds didn't work. I tweaked all the settings I could find and checked that alsa-drivers were correct. Nothing helped. Then just before I was going to post here asking for help I remembered that IBM ThinkPads have hardware sound adjustment. Pressed few buttons and sounds kicked in. I had in some point put it to mute and didn't remember it.

I was so close making total fool out of myself. And now I'm doing it anyway by telling everybody what a moron I was.