Hello.

Can you please try it in a new (temporary) Firefox profile and see if the issue is still present? See this article to know how to create a new Firefox profile. Please report back the results.

Firefox slows down dramatically because it is consuming 100% of the CPU cycles. I have tried shutting down all add-ons and rebooting. The CPU usage starts at around 25% for Firefox, with 8 or 10 tabs open. But, within an hour, the CPU usage has gone up to 100%, and Firefox is almost unresponsive. Windows Task Manager confirms that it is Firefox that is eating all the CPU, not some other program.

I hope this helps. I really prefer Firefox to any other browser. But, I can't continue this way at 100% CPU usage.

Best, Rick

That might have something to do with the plugin-container.exe. Read this article to see if that helps:

http://support.mozilla.com/en-US/questions/705108

Thanks to Morbus and silkphoenix - it took both fixes to get it working again.

Of course, it worked using the temp profile, but that meant I had no access to my bookmarks and other prefs. But, if I had not created the temp profile first, I would never have been able to apply the fix regarding the plugin-container, because FF was so slow I could never get there. I had read the instructions for that fix earlier (using IE), but I could not apply it.

Hoping it stays fixed!

Thanks to you both.

If you want to port info from one profile to another, see this:

http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

When I asked you to run a new profile, it was purely for diagnostic purposes. The fact that the new profile doesn't have the problem means there's something wrong with your old profile. It can be an add-on (please check that), or something else. Safe mode will let you set things back to their defaults without loosing your data, so maybe that will help? Check the add-ons, first and foremost, and then reset the settings if it's not an add-on.