Hi, Don. When you mentioned "Earthlink" (a server) did you meant to say "Internet Explorer" (a browser, as is Firefox)? If so, there is now an IE extension for Adblock Plus.
https://adblockplus.org/releases/adblock-plus-10-for-internet-explorer-released

And of course, John is right- you may need to used a malware detector to shovel out something noxious that is hiding on your computer. https://www.malwarebytes.org/

If these aren't helpful, at least this post will keep your request under the spotlight.