Upgrading to Monterey 12.5.1

I have a compatible 2019 Mac Air running Mac OS. Attempting to upgrade to Monterey while installing the latest security updates. When I click on the upgrade button, it takes me to a screen indicating that the Mac must be restarted. Then, nothing happens (for over an hour) plus I cannot exit from the upgrade program to manually restart the system. Additionally, even my shut down is disallowed because of the Monterey upgrade program. I seem to be frozen a bit. Does anyone know what is happening here and how to escape?