why doesn't AdBlock, for Firefox, work anymore?

Perhaps you disabled it by mistake. Click on the little "stop sign" icon, and check your options.

1. Uninstall Adblock Plus and restart Firefox.

2. Type about:config in the address bar and press Enter. Press the big button to bypass the warning. In the Filter: bar, paste extensions.adblockplus. If there are any entries that appear in bold text, right-click each one and choose Reset.

3. Exit Firefox from File > Exit.

4. Open your profile folder. Delete the extensions.ini, extensions.cache and extensions.rdf files and if found, the adblockplus folder.

5. Install Adblock Plus.

1. Make sure its enabled and updated, tools -> addons, should be version 1.3.9

2. Go into its options (Ctrl+shift+e) and make sure you have a current subscription and update it, i would recommend "Fanboy''s List"

3. its good but not 100%, its not uncommon for specific sites not to work properly with it, just stay on top of updates it usually sorts itself out.