Pop-up Blocker blocks pop-up windows. Sometimes pop-up windows are ads, but not always. Some sites use pop-up windows for legitimate, functional purposes (displaying information about something on the page, for example; you can allow those sites to use pop-up windows and block all other sites). Ads on web pages are still displayed and not affected by Pop-up Blocker. About Pop-up Blocker and Pop-up Blocker settings/exceptions: http://support.mozilla.com/en-US/kb/Pop-up+blocker<br /> Pop-up tests (to verify it is working; this is a reliable source): http://www.auditmypc.com/popup-test.asp To block some advertising on web pages install this: https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/ *After install and re-start, be sure to choose a filter list: https://adblockplus.org/en/subscriptions **I use Easy List (English) and Malware Domains (under Miscellaneous, near the bottom); works well for me. *AdBlock Plus home/getting started page: http://adblockplus.org/en/getting_started '''If this reply solves your problem, please click "Solved It" next to this reply when <u>signed-in</u> to the forum.''' ------------------------- Not related to your question, but... You need to update some plug-ins: *Plug-in check: https://www-trunk.stage.mozilla.com/en-US/plugincheck/ *Adobe PDF Plug-In For Firefox and Netscape: [https://support.mozilla.com/en-US/kb/Using%20the%20Adobe%20Reader%20plugin%20with%20Firefox#w_installing-and-updating-adobe-reader Installing/Updating Adobe Reader in Firefox] *Shockwave Flash (Adobe Flash or Flash): [https://support.mozilla.com/en-US/kb/Managing%20the%20Flash%20plugin#w_updating-flash Updating Flash in Firefox] *Next Generation Java Plug-in for Mozilla browsers: [https://support.mozilla.com/en-US/kb/Using%20the%20Java%20plugin%20with%20Firefox#w_installing-or-updating-java Installing or Updating Java in Firefox]