Log into your cPanel account and click on phpMyAdmin
Open the database that your Joomla website uses
Click on the *_users table. The full table name has a prefix and will look similar to jos_users.
Find your admin user and click on Edit.
Change the password field to "5f4dcc3b5aa765d61d8327deb882cf99". This string or hash changes the password to "password"
(without the quotes)
Now, attempt to log into the Joomla admin with your new password