You should keep your Linux software up-to-date.

Many distros of Linux have Firefox installed as the default web browser. If it is a browser installed by Linux it should update as the rest of the Linux software updates. Many Linux distros do not use the ordinary Release they use the ESR that updates less frequently than ordinary Releases. Firefox ESR will currently be transitioning from Fx45 to Fx52

• See https://www.mozilla.org/firefox/organizations/faq/

You certainly should not still be on Fx35

If you need a password to use Administrator features in Linux you will need to get that sorted out. Quite possibly Linux may encrypt your Home partition and you may need to take steps to ensure you have the correct pasphrases for you to be able to access and Use Linux.

I suggest you ask for advice in a suitable Linux forum.

You should be able to Install a Mozilla build of Firefox using your current Linux User account the instructions are here:

• Install Firefox on Linux

If you are using Firefox from www.mozilla.org/firefox/all/ make sure the Firefox folder has read/write permissions for the account user to do updates. If you are the only user then a easy way is to have Firefox in Home.

Note you appear to be using a rather old version of Firefox 11.2 as Adobe has been supporting Linux again with current Flash Player branches since mid December.

The current Flash Player version for Linux and Windows is 25.0.0.148

Verify that you meet the System Requirements (GTK+ and GLib) for the current Firefox release.

• https://www.mozilla.org/en-US/firefox/53.0/system-requirements/

Firefox ESR:

• https://www.mozilla.org/en-US/firefox/52.1.0/system-requirements/
• https://www.mozilla.org/en-US/firefox/45.9.0/system-requirements/