So I've tried lots of different things, but none of the places I look seem to have the exact problem I have. I used Avast Driver Updater, and now my volume control doesn't work. There is a little red X next to it on the task bar, and when I hover over it, it says "No Speakers or headphones plugged in" but when I click volume control, it starts troubleshooter, aka "Detecting problems". There is no volume bar to raise, lower or mute volume, even though my pc is plugged into my tv by HDMI lead.

I now worry that I may of made things even worse, as some of the advice given by youtube videos and tech websites involved uninstalling things, and now my HDMI connection to my TV, isn't even on the list of options in the Playback Devices.

I get the sound bar back when I plug headphones directly into my desktop, but it goes away as soon as I unplug them.