If you see a trial screen, click on "license this software". I forget if you have to sign in with your Adobe ID/password before or after, but it will give you a serial number option. That is you would see a button, "I have a serial number" or a screen where you input your serial number.
Once accepted, your software will go back to its' licensed state.
Also if you still have problems be sure you are still not on any 30 day Cloud plan that you must cancel. Uninstalling CC may not be enough.
Contact Customer Care to cancel your trial or plan.
You are brilliant and quick to answer. Many thanks,