Trouble may have other suggestions but if the volume meters are not showing sound levels then you are not getting any from your system. You might enable the speaker and headphone outputs to see if they might be moving.
Basically all I might suggest is to change the default device temporarily then change it back. Perhaps that would reset something. If it isn't that and your sound devices show no yellow triangles then I will go back to the possibly of the sound being muted or turned way down.
In the Device Manager at the top of the listing is shows Audio inputs and outputs, do they agree with the other panel?
Otherwise, I have no other suggestions.