Many site issues can be caused by corrupt cookies or cache. * Clear the Cache and * Remove Cookies<br> '''''Warning ! ! '' This will log you out of sites you're logged in to.''' Type '''about:preferences'''<Enter> in the address bar. * '''Cookies;''' Select '''Privacy.''' Under '''History,''' select Firefox will '''Use Custom Settings.''' Press the button on the right side called '''Show Cookies.''' Use the search bar to look for the site. Note; There may be more than one entry. Remove '''All''' of them. * '''Cache;''' Select '''Advanced > Network.''' Across from '''Cached Web Content,''' Press '''Clear Now.''' If there is still a problem, '''[https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Start Firefox in Safe Mode]''' {web link} While you are in safe mode; Type '''about:preferences#advanced'''<Enter> in the address bar. Under '''Advanced,''' Select '''General.''' Look for and turn off '''Use Hardware Acceleration'''. Poke around safe web sites. Are there any problems? Then restart. ---------------- check this: * see if there are updates for your graphics drive drivers '''https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration''' * disable protected mode in the Flash plugin (Flash 11.3+ on Windows Vista and later) '''https://forums.adobe.com/message/4468493#TemporaryWorkaround''' * disable hardware acceleration in the Flash plugin '''https://forums.adobe.com/thread/891337''' See also: * '''http://kb.mozillazine.org/Flash#Troubleshooting'''

Make sure that you haven't enabled a High Contrast theme in the Windows/Mac Accessibility settings. *http://windows.microsoft.com/en-us/windows7/turn-on-high-contrast Make sure that you allow pages to choose their own colors. *Tools > Options > Content : Fonts & Colors > Colors : Override the colors specified by the page with my selections above Try "Never" if the default "Only with High Contrast themes" isn't working. This setting affects background images. See also: *http://kb.mozillazine.org/Website_colors_are_wrong