1) Log into the phpMyAdmin of the OS Commerce application database
2) Select the administrators
3) Click on the Browse
4) Click on the Delete
button to delete the existing administrator password.
5) Go to your administrator login page. (if your OS Commerce is installed on your domain, you should be access admin page by http://domain.com/admin). You will be able to see the message as below.
No administrators exist in the database table. Please fill in the
following information to create the first administrator. (A manual
login is still required after this step)
6) Insert the new username and password and click on the Create Administrator
7) Now you can log in with the new login detail.