I take that to mean that you can see your bookmarks and history okay, but clicking on them does nothing.

Try closing Firefox File>Exit or "Firefox" > Exit

Then check "Processes" tab of the Windows Task Manager to make sure Firefox is down, if you don;t know how it won't really matter as the next step is ...

Shut down and restart your system, and then restart Firefox.

A possible cause is a problem with the file places.sqlite that stores the bookmarks and the history.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.com/kb/Bookmarks+not+saved#w_places-database-file