Hello,

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.

Thank you for your reply. I have not yet disabled the "Hardware Acceleration". Up to this point, Firefox has been irratic and unpredictable. Sometimes Firefox will perform perfectly....fast with no problems viewing video or any other part of the Internet. Then, without warning the screen will go dim and lockup my computer. Finally, I have received an error message regarding a busy or unresponsive Script. The following is a description of what showed up on my computer screen: Script: resource://gre/components/nsUrlClassifierLib.js:1277

I am not a programer, but it appears that Firefox has a problem with some Library file. On July 3, 2013, Ubuntu suggested that I download an upgrade for Chromium and Firefox. I believe (not sure though) that the download was for video drivers. After I completed the download, Firefox was preforming great....FAST with no problems with any aspect of the Internet... even viewing videos. Then on July 5, 2013, Ubuntu suggested that I download some upgrade for some Library files. After completing that upgrade. I noticed the same problem of the screen dimming and computer lockup.

I hope that this new Error Message information may provide a clue to some genius programer to help them solve this problem. Again, thank you for your help.

Hello,

Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Thank you.

Well, a lot has changed since I last wrote. I have upgraded to Firefox 22.0 which did not help my problem too much. Forgive me but I did NOT want to disable anything because my computer is only a year old and for me is fairly new and high powered. I discovered that Adobe is no longer supporting the Flash graphics driver for Linux systems. Upon the suggestion of one of the Mozilla help pages, I decided to download a graphics driver from AMD. After all, AMD created my A8 APU (Quad core processor with integrated Radeon HD 6620G gpu). If anybody knew how to take advantage of graphics acceleration for this processor, it should be AMD. I had to answer several questions to isolate my specific processor, but I made the proper selection to download. IT TOOK FOREVER. First I had to download from AMD. Then, once inside my computer, the download had to be extracted, then installed, and configured to my system. Long story short ...... it works great!!!! Just about every aspect of my internet experience has sped up and is improved. I am very happy.

There are still occasions where the computer will still lock up, but my brother who used to work for Google gave me an explaination. Turns out if a website has some very popular information and if a large number of requests are made for the same information, that website may shut down. For example, if YouTube has a video that millions of people want to see and if there are too many requests for that specific video AT THE SAME TIME, the website will substantially slow down. The physical computing resources of the website you are viewing may also contribute to the slowness of your internet viewing. Again, the AMD graphics driver may have solved my problem and I am happy. Thank everybody for their input.