The updater wasn't able to update all the files and some were left as older versions. Do a clean reinstall. If there are problems with updating then best is to download the full version and uninstall the currently installed version.

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 6.0.x: http://www.mozilla.com/en-US/firefox/all.html

• Uninstall your current Firefox version.
• Do not remove personal data when you uninstall the current version.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.

Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

I completed the steps as you suggested and still get the same error message. Also, why am I still getting this error on a brand new computer?

I think there is a problem with FF that no one wants to correct. I had this same problem with FF version 5.0.

Also if I run FF as administrator it works fine but it is no longer my default browser. I refuse to use Internet Explorer and I don't want to use 2 or 3 different browsers because you don't have a fix for the problem.

You did delete the Firefox program folder (C:\Program Files\Mozilla Firefox\) ?

Are there any files in the VirtualStore folder?

C:\Users\<user>\AppData\Local\VirtualStore\Program Files\Mozilla Firefox

The "Application Data" folder in XP/Win2K and the "AppData" folder in Vista/Windows 7 are hidden folders.

• http://kb.mozillazine.org/Show_hidden_files_and_folders

Yes I did delete the Firefox program folder (C:\Program Files\Mozilla Firefox\).

there are no files in the VirtualStore folder.

thanks Bob

Are you using ZoneAlarm Extreme?

I've seen a few posts that ZA is causing problems like you described and in that case you need to do a clean reinstall and delete the Firefox program folder (C:\Program Files\Mozilla Firefox\) and install a newly downloaded copy of Firefox. Disable ZA before installing the new copy of Firefox.

I do use ZA Extreme Security.

I completely deleted the Firefox Folder ((C:\Program Files\Mozilla Firefox\).

I downloaded a fresh new copy of Firefox and saved it to my desktop.

I disabled ZA Extreme Security and installed FF, which opened and worked properly until I reacted ZA and I got the same error message, (Error: Platform version '5.0' is not compatiblewith min Version>=6.0 max Version<=6.0). I surely cannot browse the Internet without any security and I have 6 months left before my ZA is due for reinstatement.

Based on what I have read about in this forum there is no security system that is compatible with any version of FF.