HDMI wont produce sound on VIZIO HDTV?

ive seen a lot of people have troubles with hdmi and audio when dealing with hdtv (it works fine on my regular flatscreen but I got a new one) how do you fix the audio? I am using windows 10 and I cant find anyway to fix it. I do see the tv as an option for the audio but when I make it my default half the time all the sounds stil come from the Realtek Digital Output and even when the sound does switch to the tv audio it doesn't play any sound whatsoever (really har dot play games or anything since there is no sound lol id settle for the dial up screeches right now haha.

thanks for any help you can provide.