Delete the file cert8.db in the Firefox Profile Folder to restore deleted root certificates.

• Help > Troubleshooting Information > Profile Directory: Open Containing Folder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I deleted some certificates too and now I can't access Facebook (don't even know what other sites won't work either). I looked for the cert8.db file but I can't find it anywhere. HOW can I fix this?? Thanks!

I found the cert8.db file & removed it but nothing has changed...still can't use Facebook. Any other ideas?

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