I cannot find setting that made sound crash, so unfortunately I am getting ready to reinstall system, and yes after everything is set up I will back up system partition.
Before somebody starts posting about that, yes I have installed in a partitioned disk, but I might just re-install without partitions, since all my data is in a 2 GB external HDD.
If any suggestions arrive after this post, I will implement them, since this is not imminent, I am preparing very carefully, and I have another computer with sound.