Sorry I forgot. After you disable it you can then delete it in Search Everything. Some software does not allow deletion unless it is first disabled.
Manually editing the registry for hundreds of obscure entries is a crude method of uninstalling evil software when compared with doing a simple system restore. I had actually started with the registry edit method, then gave up when it appeared it would take forever.
Of course, the best solution is for Avast to not insidiously install evil software. (Any software that installs itself without the user's knowledge and consent and cannot be uninstalled by any of the routine methods is evil.)