access denied means, there is a permission problem.
In case you are logged in with administrative permissions, then you shouldn’t have that problem unless something with the permissions in the relevant registry branches is messed up for whatever reason.
At the moment I have no idea if there is a way to restore the default permissions apart from repair install, reinstall or recover from a recent backup or system restore.
In case you have no administrative permissions, then this might be normal after hardware changes (inluding firmware updates). Logging on as user with admin priviledge should then fix that.
I checked my current login and it shows as having administrator privileges. I will give this a few more days to see if another response comes. If not I will give a repair install, I really can not do a full install because I have so many old programs I don’t want to reinstall, plus some passwords saved on programs. Thanks