How can I automatically start Oracle on Windows?

First solution:

Set the "HKEY_LOCAL_MACHINESOFTWAREORACLEDATABASE_STARTUP" key in the Windows95 Registry to value "AUTO". To disable automatic startup set the value to NOAUTO.

Second solution:

Put an icon for SQL*Plus or Server Manager in your startup group. The command line for Server Manager must include a SQL script that contains the same commands you use to startup Oracle. Eg:

SVRMGRxx COMMAND="@startup.sql" sqlplus @startup.sql

All of this assumes that you have the Oracle services set to startup automatically upon system startup. This is the default upon installation. Your startup script should look like this:

SPOOL STARTUP.LOG
CONNECT SYS AS SYSDBA
STARTUP
SPOOL OFF
EXIT