Try to disable hardware acceleration in Firefox.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

• https://hacks.mozilla.org/2010/09/hardware-acceleration/

A possible cause is security software (firewall,anti-virus) that blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

Interesting that security software is the problem. I had the same security software for the past 4 years with earlier versions of Firefox and it never caused a problem. I find it odd that now all of a sudden it's a problem. Sorry, but I don't buy it.

Neither the disabling of hardware acceleration or resetting of security worked. It simply takes too much time to load pages not related to what I've requested. I ask for my email and it loads a background page on sports, etc.

Found the answer in another part of the forums. Uninstall Firefox, but leave your personal information (bookmarks, etc.) Reinstall Firefox. That worked for me!