Unable to log into Front end and Administrator Panel of Joomla with correct login and password

Today, I’ve fixed another problem with Joomla. My client was unable to login to Joomla Administrator Panel with his correct login and password (and Super Administrator rights). Solution of this was very easy.
You should open phpMyAdmin (or any other DB manager) find table jos_plugins, find record for plugin “User – Joomla!” and set “published” field to 1 (some guys on forums say that sometimes with same problem helps changing 1 to 0!).