You mention problems with Firefox 9, 10, and 11. Have you used these versions one at a time over a number of weeks as they update (or are you trying to run all these at the same time ? ).

I am guessing you may have bookmarks and possibly passwords etc that you may wish to retain. First of all backup your profile, and your bookmarks (they are also in the profile) put them somewhere safe outside the Firefox program and profile paths ( Win 7 Desktop is a suitable location ) see

• backing up your information
• backing up and installing Firefox
• I am assuming one user and only one version of Firefox do not proceed further if that is incorrect
• you may want to ensure you have bookmarked any add-ons you need

1. (after creating the backups)Use IE to download the installer file for the current Firefox release from http://www.mozilla.org/en-US/firefox/all.html
2. Uninstall Firefox, use the Win7 Control Panel,
   • accept the delete personal information option
   • restart the computer, check Firefox has gone, and that the profile folders are also deleted
3. run the installer file to reinstall Firefox ( ? May need to disable security software )
4. check Firefox Works
5. install add-ons one at a time, checking each one works

See also

• software Update failed
• updating firefox

Post back with how you get on.

Thanks John99 for trying to help... Let me clear some of this up, my problem started with FF 6 , then 7 , 8, 9,10 and now 11 ALL one at a time. I tried your suggestion of uninstall , reinstall of FF 11. But nojoy still had same problem, BUT !!! I have found the solution.... Firefox worked great up until I upgraded from 3.6, as I said with every upgrade of FF my problem with Add ons ,Plugins and extensions being disabled on bootup came with them. I tried every solution I found in the support forum but none helped, But I have found that my problem was with my Anti Virus. I was running Bitdefender 2010 Anti Virus and even if I shut it down my problem was still there.I was pretty much done I couldn't find the answer then for an unrelated reason I was looking on the BD web site and found this FREE upgrades to 2012 for ALL CUSTOMERS....so I did the upgrade and just like that my FF problem is gone !!! Hope this helps others that may still be fighting this. Just remember to check the system requirements first on there web site .

Thanks for posting back, so we now know that bit defender 2010 my cause problems with Firefox. The reason I mentioned in the last post checking that firefox was still absent on a restart was that I was aware some third party software could be reverting or blocking changes you were attempting to make.

I do not know from your reply whether the upgrade to bit defender was essential to solve the problem, or if bitdefender 2010 settings could have been changed to resolve the issue.

As you say bitdefender is offering free updates that seems worth taking advantage of. In any event AV will need constant updating as threats change, but hopefully that is a separate process from accepting an updates from bitdefender 2010.

P.S.
There have been other posts suggesting bitdefender upgrades are needed e.g. /questions/896729

To be honest I'm not sure if setting changes in Bitdefender 2010 would help. I personally tried different settings plus turning it off but still had the problem. And Yes upgrading to 2012 was essential to solving my problem.

Here are the Software requirements from Bitdefender to run 2012....The 2 that stand out to me were .Net Framework 3 and Firefox 3.6 and Higher. Because that's when my problem started , I mean the upgrade of Firefox higher then 3.6...Many times I went back to 3.6 to get away from the problem...Hope you can figure it out..Thanks for the help though... Software requirements:

   Internet Explorer 7 and higher
   Yahoo Messenger 8.1 and higher
   Firefox 3.6 and higher
   Thunderbird 3.0.4
   Outlook 2007, 2010
   Outlook Express and Windows Mail on x86
   .Net framework 3

Thanks Backpain,

The other thread I looked at concluded an update was necessary and you have also tried changing settings with Bitdefender 2010 and disabling bitdefender 2010 before coming to the same conclusion. As the up date is free to bitdefender customers and no doubt has other benefits it appears to be the correct course of action..