command prompt > oradim -new -sid snd2

set oracle_sid=snd2
make the directories
copy the pfile of an existing database and change the database parameters
sqlplus /nolog
conn / as sysdba
startup nomount pfile='<the pfile with the absolute path>'

create database snd2 
maxlogfiles 100
maxlogmembers 5
maxdatafiles  100
datafile 	'd:\mydb\snd2\database\sys_01.dbf' size 100m,
	'd:\mydb\snd2\database\sys_02.dbf' size 100m
logfile 	'd:\mydb\snd2\database\redo_01_1.rdo' size 10m,
	'd:\mydb\snd2\database\redo_02_1.rdo' size 10m
undo tablespace UNDOTBS1 datafile 'd:\mydb\snd2\database\undo_01.dbf' size 50m
/

SQL Prompt > @$ORACLE_HOME\rdbms\admin\catalog.sql
SQL Prompt > @$ORACLE_HOME\rdbms\admin\cataproc.sql