no sound on iMac running openSUSE 12.1--is this the right driver?

iMac uses Nvidia Corporation MCP79 High Definition Audio. I did a search and found this driver

It was at this site.

Is this what I need?

I assume this is Gnome since you have file roller. Have you installed pavucontrol and paprefs?

I actually am asking for a friend who is running openSUSE per my suggestion. He is running Gnome 3. I just visited the package search page and found pavucontrol and paprefs. I will let him know that he needs to install both of those.

I think the answer is NO.

So are pavucontrol and paprefs all that is needed to get sound working?

It’s a good start. I don’t believe that driver you downloaded will will get you anywhere except into trouble. In my experience, it’s tough to try to solve a problem by proxy. Can your friend get online and research this issue himself? Also, have you googled for this card and Linux?