The default admin password is no password, unless you have actually created an administator password for it. You can try to login without password (just press <Enter> key at the password box) and see that is the case.
Re-installing the software actually will not remove the admin password. For security reason, we will email the instructions on how to reset your admin password to you. The procedure work only if you have physical access to the computer running the TLserver so remote hacker will not be able to breach the administrator role.