That was also what I was thinking...
Once an OS is (even slightly) damaged then you have to restore it by re-installing or re-imaging it.
Sorry but that's the only solution.
Or disabling Security Center, Windows Defender and Windows Firewall and ignore those useless warnings from Security Center, because as Comodo GUI says, everything in Comodo is enabled and the system is properly protected. I wouldn't leave Comodo just because of such an irrelevant issue. If Comodo was not working properly or not protecting the system, then that would be the case, but giving up due to a simple problem when registering to Security Center is not reasonable in my opinion. Security Center always had problems with malfunction since the Windows XP era.
Also by Installing/Uninstalling Comodo and Kaspersky multiple times, his Registry is most likely a mess and his Security Center iteration is most likely corrupted due to that. I think he is doing this (switching between Comodo and Kaspersky) at least once per month, due to (mostly) irrelevant issues.
Not trying to be offensive but I can't help but wonder if this is related to mental instability issues? If he does not trust in Comodo, and keeps leaving due to simple things only to return later, and leave again, then he should leave it permanently and use something else that he feels entirely comfortable with.