I'm trying to set up Contact Scoring for my subscribers, 9 months after creating the database. I've added the Campaign Activities, but none of the contacts have a score. How can I update all the contacts so they show a score?

My goal is to ultimately look at all the subscribers who have never opened an email from us, and remove them from the database. Knowledgebase told me to create a segment on 'never opened' but I wasn't able to do that anyway.