I have this exact problem and am very frustrated: I paid for avast driver update and now my sound is not working. I was unable to zoom family in lock down as a result.
Avast are not replying to me when I contact them- which I have done twice. I do not have the computer skills to sort something complex- and why should I?, that is why I pay for avast to make sure my computer works well. I phoned Avast but because I don't live in the US they don't provide that service to me. I don't want to restore to factory reset as then I will have to spend hours re-setting up my computer.
Avast please can you contact me asap and sort this out on my computer. Thank you