Ok, simply log into your DirectAdmin control panel, and open phpmyadmin (you will need the database account and password and that can be found in the config file for the CMS.) Once logged in to phpmyadmin and the database is selected, locate the cms_users table. Identify the admin account by clicking Browse, then click the SQL button at the top of the page.
In the field marked "Run SQL query/queries on database " paste one of the following queries: (both will reset the admin password to "admin")
UPDATE `cms_users` SET PASSWORD = md5('admin') WHERE user_id =1;
UPDATE `cms_users` SET PASSWORD = '21232f297a57a5a743894a0e4a801fc3' WHERE user_id = 1;
After logging in with the "admin" password, make sure you change the password to something you can remember :)