10 hrs since CIS last time has updated itself (well signatures) and manual updating gives error when CIS tries to install signatures. Diagnostics says no problems and no logs.
It would help to explain the exact error message you get for the AV install stage, and not the ones you find in windows event viewer as those are not related to your issue and can be ignored.
Try deleting all .cav files in ProgramData\Comodo\Cis\Signatures also delete any temp files found in ProgramData\Comodo\Cis\wpTemp except for the certupd and urls folder.