As stated in the title, in Classic, my boss deactivated a "Running User" who created the President's Dashboard which then disappeared. The deactivation was performed because that person is no longer with the company and my boss needed to free up a seat to grant me administrative privileges and place me as the new Running User on all Dashboards and to allow me the abiity to run the Lightning Compatibility Test.
I attempted to reactivate the former employees account; so as to allow the missing Dashboard to repopulate. However, because there are no remaining seats, I only got a red flag error message telling me there's no room at the inn.
The data from the vanished Dashboard is still searchable in our Org as well as the Dashboard record (although empty).
What is the easiest method of reconstructing the President's dashboard?