Thx for all you how helped me go through this.
The case is solved.
It was a conflict between the nvidia sound and the onboard sound.
When I uninstalled the realtek MSi audio driver and disabled the onboard sound in Bios I was able to get the nvidia to play sound through one HDMI cable to the Bose receiver.
I wasn't happy because I lost the video quality and I want multiple monitors. I got back to the realtek on board sound . All I had to do is to uninstall the Nvidia audio, get an optical cable from MSI board to the Bose receiver and Voila. Sometimes the solution is very simple. I wasted so much time just because I missed to uninstall nvidia driver and leave only the Realtek. Now you might think : DUH - how can you miss that. Well it can happen to anybody to miss the right solution, that's why we have these forums to help each other.
Once again THX to Everyone!