First and foremost thing u need to create an instance using oradim utility of oracle.U have the option to create the password for the sys(9i) in that command it self or u can also create it later using orapwd utility.
Start the instance from services dialog.
>sqlplus sys/passwd@tnsservicename as sysdba--for 9i only
Shutdown the instance and restart it to check for any errors.
sql>issue ur db creation command.
After successfully creating DB donot forge to execute the sql files like catalog.sql,catproc.sql