"how old is your computer?"
2 years, 5 months. AMD Ryzen 7 1800X (8 core) with 16GB memory
"What icons were removed and windows closed?"
I got different results this time. This is the third time I've tried it.
It removed the events&tasks menu item, and closed the tasks window. After restarting the tasks and calendar icons on the far right are still there. After a second restart the calendar window is closed. F11 has no effect. If I click on the calendar icon to the far right that opens the calendar tab with both calendars disabled. F11 now toggles the today pane.