It may have happened to many of us who maintain multiple wordpress installations with very secure passwords. One day, we just forget our passwords and then realize that the email setup for the user is invalid, and we cant reset the password through email.
If it happens, there is a technique to reset the password through mysql.
Login to the Phpmyadmin control panel.
Identify the username of the account we’re about to reset from the wp_users table.
Then execute the following sql code in Phpmyadmin:
UPDATE `wp_users` SET `user_pass` = MD5('newpassword') WHERE `user_login` ='username_to_reset_for' LIMIT 1;
You may need to modify the quoted strings for your database.
Voila, now you can login with the new password.
Another GUI based method for PhpMyadmin and other ways to reset password are described in the WordPress Codex.