Try disabling graphics hardware acceleration. Since this feature was added to Firefox, it has gradually improved, but there still are a few glitches.

You might need to restart Firefox in order for this to take effect, so save all work first (e.g., mail you are composing, online documents you're editing, etc.).

Then perform these steps:

• Click the orange Firefox button at the top left, then select the "Options" button, or, if there is no Firefox button at the top, go to Tools > Options.
• In the Firefox options window click the Advanced tab, then select "General".
• In the settings list, you should find the Use hardware acceleration when available checkbox. Uncheck this checkbox.
• Now, restart Firefox and see if the problems persist.

Additionally, please check for updates for your graphics driver by following the steps mentioned in the following Knowledge base articles:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

• Upgrade your graphics drivers to use hardware acceleration and WebGL

Did this fix your problems? Please report back to us!

Thank you.

Hi Wesley,

Thanks for the reply. I tried to adjust my hardware acceleration settings in Windows 7 but couldn't. "Change settings" was greyed out.

(On my desktop: Right-clicked an empty space and selected Screen Resolution. Selected Advanced Settings. Selected the Troubleshoot tab. Change Settings is grayed out so I could not adjust hardware acceleration.)

I did go into my Firefox settings as you then suggested and un-checked "Use hardware acceleration when available". This did help somewhat, but Firefox slowed to a crawl.

I then started Firefox in safe mode and had no problem so I figured my problem might be an Extension (15 of them) and/or a Plugin (22 of them). I narrowed the problem down to my McAfee SiteAdvisor 3.6.5 Extension. This Extension did not slow my PC to a slow crawl on Firefox V27, but apparently on V28 it will. For now, I will keep this Extension disabled.

As a previous McAfee user, I can agree that McAfee does slow your computer and Firefox.

If you would like another alternative to the McAfee SiteAdvisor, I currently use Web Of Trust. Web Of Trust, most commonly called "WOT" is a user run website rating system that functions the same as the McAfee SiteAdvisor, without affecting performance.