I had CA Internet Security Suite on there, but found it confusing. I uninstalled it (using add/remove programs). However, I notice the CA icon is still in the tool tray. I do not know how to remove it or if this is a part of the problem.
After I uninstalled CA, I downloaded Avast, restarted, then downloaded Microsoft Defender, and restarted. If memory serves, the red warning box showed up before the Defender download.
Am not on the computer right now, so will attempt repair later, or other suggestions that may come up.
-Sue