Most of us are pretty sure it was a Windows update that both caused and cured it.
See the first part of Andrew's post.
Apparently it only affected 'some' systems, but a later Windows update seems to have fixed it.

I'd still mark it as resolved.
It's fixed, and I'm pretty sure we know the cause and solution.

The other users with the same issue fixed it by either Restoring or Re-Installing Windows.
You waited long enough for another Windows update to fix it.
All signs point to Windows update ..



I do not work here, but the benefits are still awesome
Make your sound your own!