How to reset my phpBB admin password?
To reset your phpBB Admin password, please follow these steps:
A) Identify the MySQL database associated with your phpBB installation
Using an FTP client, open config.php and find the following variables:
B) Access phpMyAdmin to reset the password.
1. Click the corresponding table that stores username and password information: phpbb_users
2. Click Browse located towards the top of your screen so that a list of users display.
3. Find the account of user that needs to be changed (eg. Admin)
4. Click Edit
5. From the user_password row, click the Function drop-down menu and choose MD5
6. In the box to the right of MD5, replace the existing encrypted password with your new password in plain text
7. Click the GO button located towards the bottom of the page
https://www.siteground.com/kb/how_to_re ... _password/