First, try to reset Firefox. Refresh Firefox - reset add-ons and settings. This simple step will eliminate many Firefox problems with only one click.

A few other basic trouble shooting things you can try is this: Run all Windows Updates, install all needed service packs, etc.

Update your graphics driver (Firefox uses your graphics card for some rendering, and an out of date graphics card driver can cause problems. Upgrade your graphics drivers to use hardware acceleration and WebGL

Update all your plugins (Flash, Java, etc.): http://www.mozilla.org/plugincheck/.

Download and Install MalwareBytes Anti-Malware, run a full Scan. http://www.malwarebytes.org/. This helps check that there are no viruses on your computer causing issues. You can uninstall this program after you clean off any infections.

The Reset worked..... and not only that, Firefox is a lot quicker.

Thank you very much - extremely helpful.

Glad it worked.

Bug filed. Anyone still having this issue, please give us your addons information. I have a feeling this might be related to an extension that has recently updated.

Hi Matt G, please see attached a screen shot with all my Plug-ins listed.

This issue can be caused by the value of the network.http.accept-encoding being not standard.

You can check the network.http.* prefs on the about:config page and reset all bold user set network.http prefs to the default value via the right-click context menu -> Reset.

• http://kb.mozillazine.org/about:config

Check at least:

• network.http.accept-encoding: gzip,deflate

Is the reset doesn't last then see:

• http://kb.mozillazine.org/Preferences_not_saved
• https://support.mozilla.org/kb/Preferences+are+not+saved

Can you also list your installed extensions?

• Help > Troubleshooting Information
• https://support.mozilla.org/kb/Using+the+Troubleshooting+Information+page