Ok, I followed the instructions on the site you gave. I’m now running OpenDNS. So far so good! The popups have not reappeared when “auto detect settings” is unchecked, and also when it is checked. I’ve tried running the usual websites that trigger the popup and it seems be fixed.

I’m going to run crap cleaner, reboot and then observe for any problems. I’ll let you know if I encounter anything unusual. Any other ideas to clean up the system?