Isn't there a batch file in the install location to reset the password on its database (the local one it uses to authenticate)? I seem to remember needing an email address that is registered with that install. I know the batch was there in a previous version, not used it in a while though
If your previous thread didn't answer your question perhaps some more information would be helpful.
As the current admin user, go to Settings, then Inventory or Help Desk, then User Accounts. Add a new user as admin. Then log in as new user then delete old account.