Hi beverlykingma.

On which site are you stuck know? What exactly have you done before facing the issue and cannot proceed or return back?

It is possible that your firewall or other security software blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access to install for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

• https://support.mozilla.org/kb/fix-problems-connecting-websites-after-updating

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) to see if that helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Try to start Firefox in Safe Mode by holding down the Shift (Mac: Options) key to see if that helps.

• https://support.mozilla.org/kb/Safe+Mode

Hello beverlykingma, if you are trying to update your old Firefox 6.0.2 to latest and you can not, then download and install firefox, try next steps:

1. Download a copy of the latest firefox from http://www.mozilla.org/en-US/firefox/all.html (full dmg package)

2. Trash the current Firefox application to do a clean install.

3. Install the version that you have downloaded.

Do not select to remove your personal data, your profile data is stored elsewhere in the Firefox Profile Folder, so you won't lose your bookmarks or other personal data.

see also: How to download and install Firefox on Mac

thank you