Did you try to reinstall WOT?

It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the files extensions.* (e.g. extensions.sqlite, extensions.ini, extensions.cache) and compatibility.ini in the Firefox profile folder to reset the extensions registry.

• https://support.mozilla.org/kb/Profiles

New files will be created when required.

See "Corrupt extension files":

• http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
• https://support.mozilla.org/kb/Unable+to+install+add-ons

If you see disabled, not compatible, extensions in "Tools > Add-ons > Extensions" then click the Tools button at the left side of the Search Bar (or click the "Find Updates" button in older Firefox versions) to check if there is a compatibility update available.

If this hasn't helped then also try to delete the addons.sqlite file.

I reset the extensions.sqlite, Ini and Cache files also Compatibility ini and addons sqlite, but no fix yet.

Facebook complained first, removed zonealarm toolbar, short fix. Next zonealarm update returned the toolbar. WOT, Adblock appear to be installing - ie up to the firefox restart, then nothing. Updated javi to todays version. Icons on the addressbar still greyed out.

I have also noticed that the Add-ON_Bar under the menu options keeps ending up unticked

You can check for problems with the localstore.rdf file.

• http://kb.mozillazine.org/Corrupt_localstore.rdf

Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

• https://support.mozilla.org/kb/Basic+Troubleshooting#w_8-make-a-new-profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See:

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I used the rebuild option in firefox safe mode to start again, and as expected my addons went and I have now installed both WOT and adblock, others to follow. Thankyou.

My copy of firefox has been on this machine for a very long time, so it was probably time to restart from scratch.