Uninstall CCAV, install Auslogics Registry Cleaner, on bottom left side there is "Find Registry Keys" tool button. In "Look for" field enter "comodo" as search term and delete everything it finds.
Then go to your drive C: and enter "comodo" in the search field in top right corner. Make sure you have "show hidden files enabled". Delete all Comodo folders it finds.
Make sure you do the same for all other antiviruses you've used before, just be careful if it was AVG or ESET (NOD32), because the term is too general or appears in various other general words found in registry to be searchable via registry! For avast, avira, kaspersky etc, it's fine because these words don't appear in any registry entry.
Try installing CCAV again. I've had CCAV behaving funny (disabling by itself) when I didn't clean avast! properly after uninstallation.