Thanks, I got thru to Adobe chat and found how to get to a previous version re-install via CC desktop and PsCC install underway.
We did use cleaner part way.
Will only find out if extensions work after install ...getting late now, will finish tomorrow.
I think the problem is solved.
After uninstall and reinstall PsCC, the extensions menu is no longer grayed out and one extension panel seems to work OK.
I'll need to install rest of plugins/panels/extensions, set prefs and workspace to desired setup and use for a few days before I am convinced; but seems to be working so far.
I'm writing this as case closed. But good to know if anyone else has a similar problem.
And if you ever look for PsCC install in CC desktop.....go to Apps/'find new apps'/'previous versions' from drop down list (not exactly obvious and 'all' only means new apps).