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/

Hardware acceleration is already disabled when I checked. Thanks for the suggestion though

Clear the cache and the cookies from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox/Tools > Options > Privacy > Cookies: "Show Cookies"

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if that helps.

I tried clearing the cache again, and I deleted all cookies from the sites that have issues for me, it hasn't helped at all. I tried FF safe mode again, and the websites display the same as they do in normal mode, so still broken. It doesn't matter if I use private browsing or regular browsing either. I would try rebooting the machine into safe mode, but I can't do that right now. Is there anything else I can try?

This problem has been going on for months, and I've tried everything I can think of. I even created a new user account on the PC and went to FF on that, the problem still occurs!

To see whether it is related to your Firefox settings, could you create a new Firefox profile. In addition to bypassing current extensions and custom settings, it should have completely fresh settings databases and a fresh cache folder.

Close Firefox and start up in the Profile Manager as described in the following article:

Profile Manager - Create, remove or switch Firefox profiles

A few tips on the Profile Manager:

• Any time you want to switch profiles, close Firefox and return to this dialog.
• I recommend using the default folder location suggested for your new profile (to avoid data loss, do not use any existing folder location).
• Before deleting anything, it's a good idea to make a backup first.

Do the sites display correctly in the new profile?

Also, could you review your color display settings on the following tab:

orange Firefox button (or Tools menu) > Options > Content

In the Fonts & Colors section, click the Colors button and make sure you have a checkmark for "Allow pages to choose their own colors."

The sites finally work correctly in the new profile, and I checked on my original profile for the color setting. I found that box was already checked, so that couldn't have been the problem.

Now that we know it's a profile issue, what do you think might be causing the problem on my original profile? I'd just use the new profile, but obviously I'd like to keep my saved passwords and settings.

Hi addy81, if you like research, you could review your prefs.js file and look up any preferences that seem as though they might be relevant. You can find that file here:

Help > Troubleshooting Information > "Show Folder" button

Over time, this file tends to grow, so if time is short, you could consider the following: You can migrate your bookmarks and saved passwords to a new profile by using the "Reset" feature. If you would like to try that, check out this article for the details: Refresh Firefox - reset add-ons and settings. (Slow loading right now for some reason?)

Reset copies your existing profile folder to the desktop and renames it Old Firefox Data, so if something essential turns out to be missing after the reset, you should be able to recover it from that folder.

Okay. After reading TONS of information of this (and all of it was unhelpful), I decided to test the CSS. The issue I have found is that when the CSS property "Opacity" value is set to < 1, large swaths of the printable area within firefox AND IE (internet explorer) do not render them correctly.

Check ALL CSS properties. Find opacity values which are < 1. Either:

  Delete them
  Comment Them Out /*opacity: 0.95; */ 
  Change the Opacity value to 1. opacity: 1;
  remove access to that external CSS File.

I am having the exact same problem as described here... The examples given above (Examples: beautifulpeople.com, myfitnesspal.com, mail.aim.com) only show a list of links on my browser and I can't figure out what's wrong...

I have tried clearing my cache, clearing history, removed all cookies, flushed the DNS, turned off the "Use hardware acceleration when available", turned off all my added plugins, I reset FF, and tried creating a New Profile but when I follow the steps here https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles it simply opens up FF.

I have no idea what else to do... Where is the CSS that snoopkatt talked about above? That may help me out... As a side note, I have the same issue with Internet Explorer, Safari, and Google Chrome... Could it be something else entirely?

Hi muddergrad, since you have the same issue in all browsers, have you considered whether your security software or privacy software is filtering what appears in all your browsers? This could be done either by intercepting all your browsing and blocking some files from being retrieved, or using an add-on that appears in all browsers. Hard to say anything more specific without digging around your system.

By the way, when creating a new profile, you need to fully exit out of Firefox first or the Profile Manager won't display and you'll just get a new window with your home page.

In Firefox testing in Safe Mode could help diagnose whether it is caused by an extension. That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

Tried using the safe mood with the add-ons disabled but saw no difference. I'm starting to think it may be my internet provider. I tried using a different computer through my internet connection and it had the same issue.

Sometimes, when I keep pressing refresh it will work but not always. Do you have any ideas?

I think I figured it out... After some searching online I found that the DNS could be the problem so I changed my computer's DNS to Googles and everything seems to be working now. Hopefully it continues. Thanks for the help.