If you have access to the database for the OpenACS installation you can do this:
Register as a New User, creating a new account.
After the new user is logged in, click on Your Workspace link.
Click on What other people see when they click your name.
The URL for What other people see when they click your name looks like : http://www.example.com/shared/community-member?user%5fid=12345
The user_id is the last part of the URL, in this case 12345. Remember this number.
Once you have this information log into the database using sqlplus for Oracle or psql for Postgresql.
Execute the following command for postgresql.
select object_id from acs_magic_objects where name='security_context_root';
Remember the result.
select acs_permission__grant_perission ( user_id, security_context_root, 'admin' );
Where user_id is the user_id you remembered previously and security_context_root is the result of the previous query.
For oracle:
select object_id from acs_magic_objects where name='security_context_root';
Remember the result.
begin acs_permission.grant_permission( user_id, security_context_root, 'admin'); end;
/
This will grant site-wide-admin to the new user you have created.
Now you can change passwords, add users, or grant admin to other users using this new account.
Dave