If you loose the password for your Trend Installation you will need to uninstallit manually since the uninstall program also requires the password. Below are some KSs on this subject:
Manually uninstalling the OfficeScan Corporate Edition (OSCE) 5.5 server and client.
Manual uninstalling the ServerProtect for NT (SPNT) 5.x Management Console
Manually uninstalling ServerProtect for NT (SPNT) 5.58 components