Hi,

Please check if this happens in Safe Mode after disabling all the Plugins except QT in Tools (Alt + T) > Addons.

Problematic Extensions

Troubleshooting Extensions and Themes

Uninstalling Add-ons

Uninstalling Toolbars

Safe mode disables the installed Extensions, and themes (Appearance) in Tools (Alt + T) > Add-ons. Hardware acceleration is also temporarily disabled - the manual setting is Tools > Options > Advanced > General > Use hardware acceleration when available. Options > Advanced. All these settings/add-ons can also be individually or collectively disabled/enabled/changed in Firefox normal mode to check if an extension, theme or hardware acceleration is causing issues.

Options

See also:

• http://kb.mozillazine.org/Plugin-container_and_out-of-process_plugins

Hardware acceleration was the problem. I upgraded the graphic driver ATI Catalyst Display Driver 10.6. I only have a question: the bottom of Troubleshooting Information still shows "Try updating your graphics driver to version 10.6 or newer". Will that be an issue for me? Trailers are working perfectly now - so I assume the problem has been solved.

Thank you so much for your prompt help!! :)

You can also manually enable/disable hardware acceleration: Tools (Alt + T) > Options > Advanced > General > Use hardware acceleration when available. Please note that hardware/graphics acceleration and WebGL are different. The acceleration status is shown beside Direct2D Enabled, DirectWrite Enabled and GPU Accelerated Windows.

Options > Advanced

Options

Hardware Acceleration