Hello Larry.

Hopefully this support article is what you need:

https://support.mozilla.com/en-US/kb/Firefox+will+not+start

Anyway, you may be having a problem with some Firefox add-on that is hindering your Firefox's normal behavior. Have you tried disabling all add-ons (just to check), to see if Firefox goes back to normal?

Whenever you have a problem with Firefox, whatever it is, you should make sure it's not coming from one of your installed add-ons, be it an extension, a theme or a plugin. To do that easily and cleanly, run Firefox in safe mode and select Disable all add-ons. If the problem disappears, you know it's from an add-on. Disable them all in normal mode, and enable them one at a time until you find the source of the problem. See this article for information about troubleshooting extensions and theme. You can troubleshoot plugins the same way.

If you want support for one of your add-ons, you'll need to contact its author.

I have the same problem on Win7. It is not an add-on issue. FF will not open in safe mode or regular mode. Profile Manager does not open. The process opens and runs but no window ever appears.

I have reverted to 3.6.3 for now.

Stan, please see the post above yours, as it addresses the problem you are having. Please tell me if it doesn't help you.

How do we go back to old version People keep saying they are I have tried everything listed all voe the forum and nothing works

Sandra, nobody here said they tried everything. Have you seen my post here? Please read and answer it. I hope it helps. If it doesn't, I'm following this thread by an email subscription, so I'll help you the best I know and can.

FF will only run in safe mode for me...I have tried to disable add ons one at a time and all of them with the same result FF does not respond. I've tried uninstalling and reinstalling 3.6 but with the same result. I am running XP

Woolybeth, if Firefox runs in safe-mode, with add-ons disabled, then you have a problem with an add-on. Try disabling all add-ons manually (that will include extensions, themes and plugins), and then enable them one by one until you find the source of the problem. Don't forget that it is remotely possible that there's more than one faulty add-on.

For more info, see: http://support.mozilla.com/en-US/kb/Troubleshooting+extensions+and+themes https://support.mozilla.com/en-US/kb/Troubleshooting+plugins

i figured it out it was zanga toolbar with a little research it is not compatible with the new update

3.6.4 will "sometimes" fail to load with the iMacros plugin is included. Open FF in safe mode, go to Tools/Add-ons, set iMacros to disable, and then click on Restart Firefox.

This has been identified as a bug: see the discussion here.

Morbus, the post you mentioned isn't applicable in this case. FF will not open in Safe Mode, so this isn't a problem with an add-on. Also performing a complete uninstall/reinstall does not resolve the issue.

In my case, installing any 32 bit build 3.6.4 or later the application will fail to run. The development team is aware of my issue now. Evidently there was some fundamental change with 3.6.4 that breaks the app on my system. There is apparently no fix yet other than running a 64 bit build or staying with 3.6.3.

Stan, can you please point me to the bug at bugzilla? I'd like to read the discussion.

In the meantime, for anyone who's having problems starting Firefox in safe mode, see this article:

http://support.mozilla.com/en-US/kb/Firefox+crashes+when+you+open+it#Firefox_does_not_start_in_Safe_Mode