Once the trial expires, users can typically choose to continue using the free "Premium" version, though some interface elements (like yellow exclamation marks) may persist until this selection is made. Activation Process
Even if you find a key that works for a week, Comodo’s license server regularly audits active keys. Stolen or cracked keys are added to a blacklist. When that happens, your CIS Pro suddenly reverts to the free version—or, in some Comodo versions, disables all protection until you remove the invalid key. comodo internet security license key