Security update; https://support.mozilla.org/en-US/kb/update-firefox-latest-version 50.0.2

Separate Issue; Your System Details shows;

Installed Plug-ins

Shockwave Flash 23.0 r0 Shockwave Flash 17.0 r0 Shockwave Flash 18.0 r0 Shockwave Flash 19.0 r0 Shockwave Flash 11.9 r900

Adobe Shockwave for Director Netscape plug-in, version 12.2.4.194 Adobe Shockwave for Director Netscape plug-in, version 12.1.8.158
Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer.

Flash: Grab the uninstaller from here: Uninstall Flash Player | Windows Uninstall Flash Player | Mac

Then reinstall the latest version.

Note: Windows users should download the active_x for Internet Explorer. and the plugin for Plugin-based browsers (like Firefox).

Note: Windows 8 and Windows 10 have built-in flash players and Adobe will cause a conflict. Install the plugin only. Not the active_x.

Flash Player Version: 23.0.0. 207 Flash Player (Linux) Version 11.2. 202.644

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download. <Windows Only>

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only>

See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

Shockwave Director: Shockwave Standalone Installer / Uninstaller{web link} Shockwave Director Version 12.2.5.195
http://get.adobe.com/shockwave/

Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies
  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, Start Firefox in Safe Mode {web link} A small dialog should appear. Click Start In Safe Mode (not Refresh). 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 websites. Are there any problems?

Then restart.