Try restore they:

• Restore bookmarks from backup or move them to another computer

Also try go to your profile, get one of the automatics backup in the bookmarks backup folder and restore from they:

• Profiles - Where Firefox stores your bookmarks, passwords and other user data

Also you can get the places.sqlite in your profile and try restore your bookmarks using SQLite Manager:

• SQLite Manager

To update Firefox, you can download an installer from this page (scroll down to your language):

https://www.mozilla.org/firefox/all/

You do not need to remove your current version of Firefox to install the new one, the installer will recognize your existing setup.

Regarding Bookmarks, is the problem with the Bookmarks Menu button (shows a drop-down list) or the Bookmarks Toolbar (horizontal bar).

For the Bookmarks Toolbar, try one of these methods to turn it back on:

• right-click a blank area of the tab bar
• right-click the new tab ("+") button on the tab bar
• View menu > Toolbars

For the Bookmarks Menu button, please note that Firefox hides that button if you are using the classic menu bar (the one that has a Bookmarks menu). If it is missing even when the classic menu bar is hidden, it may have moved to a different toolbar or fallen off the toolbars completely. This article describes how to customize your toolbars in that case: Customize Firefox controls, buttons and toolbars. See also the attached screenshot regarding the different buttons available.