Good day Garmina, sorry for the late response.
here is the snapshot. I can click on any menu item, but when I try to click on something in the menu or in the column of settings, the mouse doesn't work. The iMac cannot upgrade higher than High Sierra. My other iMacs have Catalina and El Capitan, they work fine.
PS. I still need the iMac with High Sierra because some programs don't work under Catalina.
Thanks Tony