This can be caused if one of the files that stores details of installed extensions is corrupt.

1. Open your profile folder, for details of how to find it see https://support.mozilla.com/kb/Profiles
2. Close Firefox
3. Delete the following files if they exist, extensions.cache, extensions.rdf, extensions.ini and extensions.sqlite
4. Re-start Firefox, it will then rebuild the list on installed extensions

I think I am in trouble. When I went to the profile folder I found 2 and both say default. One started when I got this laptop and

has the extension.cache, ini and rdf. The other started 11/09 and has the most info in it. It has extension.rdf and sqilite. What

do I do? How do I get them I am having a horrible time trying to go to the websites that have the programs I need to re-install after doing a clean re-install

of Windows 7 Home Premium 64bit. NoScript is the problem I think because not all of the page that I am on is showing ie "Choose OS,

Log In, and the dialog boxes are blank that should be filled in with something. (hope that made sense) Yesterday Firefox is not starting at times and I had to restart to get it to work. I couldn't even get IE8 to open. I have not had

that problem today. Hope you can help with this mess. Joanne

Why hasn't someone helped me? What did I ever do to ya'll? Thanks alot..................

In Firefox, use Tools > Troubleshooting Information, and locate Profile Directory then click on Open Containing Folder. That's the Profile which is being used.

That is the profile folder I have gone to. But why would I go to the profile that was done in 2009? Makes no sense but then again I obviously do not understand and at this point I don't care. I deleted again all that was given me. That hasn't helped. I was having crazy problems with FF and uninstalled, reinstalled different versions and the only one that worked is version 4. Most of my extensions are not compatible and that is one reason I wanted to go back to 3.6.8 but can't do it. At least now I can view the webpage every now and then and my toolbars are there. The bad thing is having NoScript screwed up and not being able to see the whole web page no matter what I do. I have uninstalled NoScript and reinstalled but I still get that parsing error whatever that is. What can I do now? I have again done a lot of the troubleshooting steps they have given but I don't think it will ever be right until the extensions are fixed. Thank you for replying and I appreciate your help but you don't have to anymore like I guess the first guy did. Sure did leave me hanging didn't he? I wish I could go back but I can't so I am stuck with a browser that is almost making me use IE which I abhor. Thanks again. Joanne

All the helpers here are volunteers, who contribute whatever time they have to spare after doing what they have to do to survive in the real world. Tony didn't leave you hanging on purpose, there's just too many requests for help for us to keep up with every one we're trying to help.

Firefox doesn't create a new Profile for each new major version of Firefox that is installed. It will use the same Profile folder forever, unless the user changes the Profile which is the "default" or they create a new Profile.

At this point I think you should create a new Profile and start from scratch installing extensions.
http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows

If that is successful at solving your "extensions" problems, you can copy specific files from the old Profile over to the new Profile.
http://support.mozilla.com/en-US/kb/Recovering+important+data+from+an+old+profile

Your old Profile is located here in Vista & Win7:
drive:\Users\Windows login user name\AppData\Roaming\Mozilla\Firefox\Profiles\profile_name

I am so sorry I sounded like a bitch. Tony I apologize for saying anything about you. I know you work your butts off and I feel like a troll. I hope if it ever arises you will help me if you can.

I know they are volunteers and donate their time. I was and still am having so many problems besides FF I lost it when I posted that. Please forgive me, it won't happen again. I will create a new profile and install the extension that work with 4. But I may not do it right now, I am trying to re-install win7 to factory reset and I will have to start everything over again. If I don't have to, I will let you know when I have a new profile. Thank you again and thank you for allowing me to stay in this forum. Joanne

I tried to fix the sentence from leaving this box, but don't know how. :(

Fixed. That was caused by a leading space at the start of a line of text.

Good luck with that factory reset. Let us know how it goes with Firefox afterward.

I was successful and created a new profile and got all my bookmarks!!!!I am installing add-ons and have not had a problem. So it's fixed thanks to you. But I still don't know how to re-install win7. Can you suggest a place for me to go? I haven't had too much luck with toshiba but I will try again there. I'll find out how to do it somewhere. Thanks again for your help. I never thought I would be able to use FF again and I was heart broken. So you made my heart smile.  :) Joanne