Welcome SeppSchrot! Appreciate your input. At this point we're not much help but still working on finding cause of the problem. Nvidia may already know but they have not said anything. Morrow indicated that a statement from them may be forth-coming. Hope so, this has gone on a little too long. At this point I just hope there is a fix!
I can make it happen on a 5900U that normally does not suffer from flickering or the sound problem but only in one instance so far on one screen and nowhere else. I can do the same with a 9800Pro. ActiveX may be involved but I cannot verify that yet.