Well, I am new to openSUSE, but I also had a problem with the sound and solved it.
Try this (assuming you have a Gnome Desktop like me):
[enter root password]
->Security and Users->User management
Select your username
Click on edit
Open the "details tab"
Check the "audio" group on the right
And then it should eventually work.
I'll try finding the topic where I learned this.
Maybe there's a general command-line way, because I don't know how it's in KDE.
Here it is:
Originally Posted by puntjuh
The user probably has no access to the group audio.
open up a konsole and do su:
type ur password and press enter!
Now as root do: usermod -Gaudio `username`
without the quotations offcourse!
Now the user should have sound!