Check the View > Page Style setting and make sure it is not set to "No Style".

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

There are other things that need your attention.

Your system details list show an old Flash 9.0 r45 version that you should remove.

1. Shockwave Flash 9.0 r45

You can check if there is a file NPSWF32.DLL in the C:\Program Files\Mozilla Firefox\plugins folder and remove that file if present.

You can set the plugin.expose_full_path pref to true on the about:config page to see the full path of plugins on the about:plugins page.

• http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins
• http://kb.mozillazine.org/about:plugins
• http://kb.mozillazine.org/about:config

It is best not to leave that pref set to true as it exposes that full path to web servers via the navigator.plugins object, so reset that pref to false after you are done with the about:plugins page.

See "Manually uninstalling a plugin":

• https://support.mozilla.org/kb/Troubleshooting+plugins

Thank you for your reply. I checked this and it is set to Basic Page Style. I don't have this problem on every page. This one for instance works just fine. The ones I have found so far are twitter and all of the apps/theme page.

Doing the Firewall part now. Have to shut down firefox first. Thought I'd reply to this first. I don't know that Kaspersky is the problem. It is the only firewall and antivirus I am running. Since I can connect to the internet on Firefox, but I am going to do the steps. If I do not reply that it is fixed, please assume it is not.

I did all the steps for removing the Shockwave 9.0 r45. It says to just rename that dll. I did that. Should I delete it though, instead of having an unecessary .dll hanging around? And I don't know if that would've helped the issue, but it has not. I appreciate your help.

Any other ideas would be great. I don't remember if I mentioned it, but I also did the reset Firefox step I found in one troubleshooting part to no avail.

Attached an image of the issue.

Thanks again! Kelly

PS: I forgot, also I have many times also received the this site is not trusted thing with the certificate issue. Attaching a pic. It's a pic of a window being shown in a window, and that window has a certificate not trusted. I believe these issues might be all related. This was also happening from the beginning.

You seem to be missing all the CSS files on the Twitter page.

Does the Net log in the Web Console (Web Developer > Web Console; Ctrl+Shift+K) show that Firefox retrieves them?
You can remove the check marks in the CSS drop down menu to avoid CSS errors from cluttering the display.
You need to do a hard reload (Ctrl+F5) to refresh the page after opening the console.
The GET entries should show a HTTP/1.1 200 OK response.

• http://twitter.com/ (main page)
• http://a0.twimg.com/a/1350590550/t1/css/t1_core_logged_out.bundle.css
• http://a0.twimg.com/a/1350590550/t1/css/t1_more.bundle.css

See also:

• https://developer.mozilla.org/en/Tools/Web_Console
• https://developer.mozilla.org/en/Using_the_Web_Console