hello, please go through the steps covered in Websites look wrong or appear differently than they should - they contain the most common solutions for the issue you've described...

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

"Clear the Cache":

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

"Remove Cookies" from sites causing problems:

• 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

i found how to fix it guyz and it really works just check if your computer time is right and then update you inter net time and itzzz fix

email me if you need help

By the way, if you use a Samsung system (esp. Windows 8 systems) and find that clearing the cache fixes it for a while but eventually problems recur, this could be due to a feature of the Samsung Help Center software. This is discussed in other threads.