Can't get audio to work

Hi,

I have windows 8.1 installed on my d34010wyk NUC HTPC connected to a samsung smart TV with HDMI cable.

The problem is I can't get audio to work. The digital audi source shows as unplugged.

I know the problem is not with the TV because I plugged another computer on it and it was working fine.

I tried uninstalling and reinstalling the latest drivers but nothing.

Thanks in advance!