Resolved Question: How can I remove adware & spam? In replying to people who answered my personal ad I now have spam & pop-up.?

Pop-up from ad.yieldmanager.com (link broken) trying to open my Trusted Sites list now periodically comes up every time I reply to an email. I’ve added some spam addresses to my block list, but most of it looks like the same sender with a slightly different address for each email. Can I get to the root sender to stop it?