To reset a lost Joomla admin user password log in to the MySQL database and set the password field in the jos_users table to:
d2064d358136996bd22421584a7cb33e:trd7TvKHx6dMeoMmBVxYmg0vuXEA4199
This will allow you to login as admin with a password of secret. Reset the password from within Joomla afterwards.
