Ctrl+Shift+Del > Cache > Clear now !

A possible cause is security software (firewall) 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 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.com/kb/Server+not+found
• https://support.mozilla.com/kb/Firewalls

Thanks for the suggestion about the plug-in container. I now have that unconditionally enabled along with Firefox in my firewall. Unfortunately, it didn't resolve the problem.

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Thanks for the suggestion. I didn't know cache could be cleared that way. Unforunately, it worked for a while but later failed.

I've cleared my cache, restarted the browser, restarted the computer, disabled all addons, the problem keeps coming back. Not a net issue since Opera and IE work fine. I've found that force refreshing the web page with F5 or clicking the refresh button will eventually fix it but then my icons get all jumbled up. It's like it can't figure out how to load images anymore. When it gets stuck trying to load the image and I force refresh, it just grabs some other image and saves that. This results in strange behavior like Accounts icons being saved as logout.jpg and such. This behavior can be seen on cybernations.net, chase.com and wunderground.com. I'm sure there are several others as well but those are the ones that I find myself force refreshing to load most often. I am using Aurora and FF6. Both versions exhibit this behavior.

I found a solution that seems to work for now. Whether this will be a permanent fix or not... time will tell.

Basically, I reset my Firefox preferences to the defaults and things started working again.

Go to your Firefox profiles folder (if using Win7, C:\Users\username\AppData\Local\Mozilla\Firefox\Profiles\gibberish.default\)

Make sure to shutdown Firefox.

Find the prefs.js and user.js files. Get rid of them. Either delete them or move them somewhere else.

Start up Firefox again and your pages should (hopefully) load more quickly and correctly now.