Diagnosing firefox problems
Unknown Plugin Issues
This inormation was lifted wholesale from here.
Issues of this sort are, unfortunately, more common and the we'd like them to be. However, they tend not to be cause by Firefox itself, but rather by software that is running either inside or alongside it, such as add-ons or firewalls. Since these issues have a broad span of possible causes, you need to diagnose your problems before fixing them. Follow these instructions to the line, as they'll probably help you diagnose and fix the problems you're having.
1. run Firefox in safe-mode to disable all extensions, themes and plugins. If this fixes your problem, be it with RAM or CPU usage, then you know it's a problem with add-ons (plugins, themes or extensions). Proceed to number 2. If safe-mode doesn't fix your problem, then read bellow, after this list; 2. update all extensions (go into Tools > Add-ons > Extensions > Find Updates), themes and plugins (see this page in your Firefox. If this doesn't solve the issues, proceed to the following number; 3. disable all extensions, themes and plugins in your Firefox (not running safe-mode). This is temporary and for diagnostic purposes only. Being certain that, as in safe-mode, the problems you're having have gone away, enable one plugin at a time. You should be certain that you actually want that plugin to be enabled. It's best to keep the overall number of enabled plugins as low as possible. When you encounter problems, you know you've found a problematic plugin, so disable it for good. Keep enabling all plugins (except problematic ones) until you've gone through them all. If you need support for a problematic plugin, you need to contact its author for support; 4. enable one extension at a time. Again, be certain that you actually want that extension to be enabled. As with plguins, it's best to keep the overall number of enabled extensions as low as possible. Also, try the theme you want to have installed so see if that is what's causing the problem. When you encounter problems, you know you've found a problematic extension/theme, so disable it for good. Keep enabling all your extensions (except problematic ones) until you've gone through them all. Just the same as with plugins, if you need support for a problematic extension/plugin, you need to contact its author; 5. if you've followed my instructions above, you're done! You've fixed your problems with problematic add-ons. If you want to keep using those problematic add-ons, please contant their authors for support.