It is very common thing for clients having Joomla based websites to forget their password. It is possible to reset password from jos_users table using PhpMyadmin. But it is much
# mysql -u root -p
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 975975
Server version: 5.1.66-0+squeeze1 (Debian)
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> USE joomla_site;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
mysql> UPDATE `jos_users` SET `password` = MD5( ‘new_password’ ) WHERE `jos_users`.`username` = “administrator” ;
Replace "new password", string with whatever new password is necessary
Change “administrator” or admin with joomla's admin username.
There you, go Joomla admin password is changed