How To: Change or recover Joomla Administrator password

TeachmeJoomla provides you this online recovery tool. This helps you set a new Joomla password for administrator by running SQL code on the database.

This is the Joomla administrator password recovery form.

This generates the sql code to overwrite your Joomla password with a new password typed in this form.
You need to run the generated sql code in PHPMyAdmin or your favorite MySQL interface.

We do not save or give away these passwords.This is Javascript code and it runs on your own machine.
Any questions are welcome at teachme [at] teachmejoomla[dot] com. Enjoy!

For more details: http://www.teachmejoomla.net/joomla/mambo-tutorials-and-howtos/general-questions/how-to-change-or-recover-joomla-administrator-password.html

Select your Joomla database from the drop-down list on the left, then click "SQL" from the top menu. Next we enter a MySQL query which will reset the username and password.

For Joomla versions up to 1.0.12 enter the following query and click "Go"
UPDATE `jos_users` SET `name` = 'admin', `password` = '21232f297a57a5a743894a0e4a801fc3' WHERE `id` =62 LIMIT 1 ;

For Joomla version 1.0.13 enter the following query and click "Go"
UPDATE `jos_users` SET `name` = 'admin', `password` = 'af9083d4b82dbc0745b124db3b3cf15d:M0WuLowO4rtRTddG' WHERE `id` =62 LIMIT 1 ;

Note-: If you're running an older version of Joomla or Mambo, you might need to change jos_users to mos_users.

http://tutorials.ausweb.com.au/web/Tutorials/Joomla-FAQ/Resetting-Joomla-Super-Administrator-Password/

How to Reset Your Lost Joomla Password in 6 Easy Steps

Before we begin, you must have access to your database. If you don't, pass these instructions on to someone that does. It's also a good idea to backup your database before making changes, just in case something goes awry.

Finding the Password

Log in to your Joomla database (via phpMyAdmin for example)

Click to edit the _users database (will be preceded by your account name, for example: example_users

Edit the entry for where usertype = "Super Administrator" (should be the first record)

Resetting the Password
In the password field you'll notice a string of characters. Joomla uses a one-way encoding method, which means you won't be able to retrieve your old password. However, you will be able to reset the password to a new one following these simple steps:

Visit MD5Encrypter.com
Pick a new password and type it into the "encode" box; then click "md5er encode."

Copy and paste your new md5 password into the password record in the Super Admin password field and save.

Voila - you just successfully reset your Joomla password Go to your joomla domain at example.com/administrator and try logging in with the new password. You should be logged in as Super Administrator.

http://community.contractwebdevelopment.com/joomla-how-to-reset-super-admin-password