recently i do reinstallation of oxwall software- and my problem now is how to used my old database
Make sure you backup the database before anything. So if any problems arise you can just restore it.
define('OW_PASSWORD_SALT', 'xxxxxxxxxxx'); the XXXXXX part is made to secure the passwords, so if you have a new password SALT your old passwords WONT work on the new install!!! so you will need to check that out too