Problem remains unsolved.
Clicking Computing does in fact bring up the option of running mythtv-setup. Choosing it brings me to an unresponsive new page with a blank field to the upper left, which I assume should have shown the mythtv-setup screen. There is nothing to do on this screen except closing it again. I waited for several minutes in there in vain.
Clicking Computing does in fact bring up the option of running mythtv-setup. Choosing it brings me to an unresponsive new page with a blank field to the upper left, which I assume should have shown the mythtv-setup screen. There is nothing to do on this screen except closing it again. I waited for several minutes in there in vain.