When I installed SuSe 11.2 in December, there was no problem with a sound. After I started using Skype 2.1 I noticed first problems. Sometimes it didn't pick device Sis Si7012 and default didn't work. Then started problem with great noise in sound device. And KDE started warning that it detected that one of more internal sound devices were removed. Then it gave a list of SiS 7012 .... saying do you want KDE to permanently forget about these devices.
I pressed NO but it kept asking.
I tried to configure the sound card from Yast, but again problem: Kernel module snd-intel8x0 could not be loaded...
Noise is very high - practically impossible to listen. Yet when I boot WindowsXP fom other partition /no problem with sound and no noise at all?

In the skype settings, turn off the option to let skype control sound.

It started with Skype but now problem is with everything that uses sound device. For example - same problem with sound when playing DVD. As if sound device doesn't exist at all...

I will usually run alsaconf and yast2 sound. After that run alsamixer and maybe padevchooser if you use pulse audio.
If you have had alsa or the kernel updated, reboot and then make sure sound isn't muted.

If you run KDE4, run "Configure Desktop -> Multimedia".

I tried what you suggest - but it seems that 11.2 doesn't have right support for my rather old sound card,SIS 7012 onboard [Asus P4SC-EA ] AC'97 Sound Controller. So sometimes it works with noise, sometimes it doesn't see the card at all etc. Anyway thanks for help.