Please elaborate on your issue so we can better assist.

thanks

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

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

Separate Issue; Your System Details shows;

Installed Plug-ins

Shockwave Flash 15.0 r0

Adobe Shockwave for Director Netscape plug-in, version 12.1.3.153 Adobe Shockwave for Director Netscape plug-in, version 12.1.2.152

Having more than one version of a program may cause issues.

Flash is notorious for not cleaning out the older version as part of an update. Grab the uninstaller from here: Uninstall Flash Player | Windows Uninstall Flash Player | Mac Then reinstall the latest version.

Update your Flash Player v15.0.0.189 http://get.adobe.com/flashplayer/ Shockwave Director v12.1.3.153 http://get.adobe.com/shockwave/

Is the window maximized? Try to minimize. Also, move the window down from the top of the screen.