When you say "the firefox symbol", do you mean the orange Firefox button. If the orange button is missing - Right click on a toolbar space and uncheck Menu Bar and this will reveal the Firefox button. You can toggle from one to the other.

In the Firefox button>Bookmarks>Show all Bookmarks>Organize, Import etc.

That is the simple answer. You may have a more complicated problem.

Press F10 or tap the Alt key to bring up the "Menu Bar" temporarily if have the Firefox button on display and need to access the menu bar.

"Bookmarks > Organize Bookmarks" has been renamed to "Show All Bookmarks" in Firefox 4 and later.

• https://support.mozilla.com/kb/how-do-i-use-bookmarks

I have tried "show all bookmarks" but they do not show! There are there under bookmarks, but Library window is not working. so I cannot organize nor backup bookmarks. Same problem with downloads window.

See if this page helps:

http://kb.mozillazine.org/Locked_or_damaged_places.sqlite