Did you ever register the product? Adobe is very big on registering. If it phoned home and didn’t find a registration, it might explain the popup. It is then a very simple matter to get it running. Not sure why you don’t want to register since you will get support and free upgrades.
But I can't find the off switch anywhere, and the Internet is surprisingly silent on the topic, unless I haven't typed in the right code words to find what I'm looking for.