by Bruno Soldier.
Many thanks!!!!
The second of the two was exactly my problem.
I had made a point to install phpmyadmin, so taking a look at the database was easy.
The two lines of the RoleAssignments table were very different:
userid 5 contextid 46
userid 5 contextid 11
I adjusted them to 1/1 and 1/2, and now I am able to access the moodle with admin capabilities.
Thank you again, and I am now adding a 2nd administrator account.