Okay, so this has happened a couple days ago. I used to be able to connect my laptop to my tv through hdmi to watch and listen to content through the tv. But for some reason, the sound only plays through my computer, even though it is connected to the tv. I can get my tv to display everything that my computer does; it just does not play any of the sounds from it. When i tried going to the control panel and sounds to enable sound for devices outside my computer, my tv showed up as an option, but there was a small red arrow pointing down right next to the tv icon, and it said "not plugged in". it wouldn't let me set as default or configure. What is wrong? Please let me know how I can fix this. Thank you.
Go to control panel, sounds and make sure you don't have your HDMI output disable. So connect the cable to the HDMI and the tv and play something then go to control panel, right click the HDMI output and make sure it's not disable. Also if that doesn't work go to device manager and look for that HDMI uninstall it and restart your computer. And try again with your tv. See if that helps
When you are using your tv and it's connected do you see any action going on in sounds, when you are playing something? Also, you can try restoring to a day you know it was working using system restore.
I was having the same issue as you were. I was able to resolve by going into Device Manager, right click on sound, video, game controllers and choose Scan for new hardware. What showed up for me was 4 instances of NVIDIA High Definition Audio.
Then I went back to 'Playback Devices' (right click on speaker in lower right) and it now showed up there as well. Mine was selected by default and when I tested it, it now played on the TV.