I changed oracle instance to manually start from services.msc (service name is "OracleServiceORCL"), Because I want to start it up manually with SQL*Plus commands whenever I want, not with OS load.

Now I can't do that in SQL*Plus and I got this error:

ORA-12560: TNS:protocol adapter error

So I start it manually from services.msc and when database got ready I shut it down with SQL*Plus command. After that I realize that the service is still running, with very low consuming of resources.

I think this called "idle instance".

How can I automatically be in an idle instance state after I logged in to my Windows 8.1 to start oracle database whenever I want with SQL*Plus commands, not manually from services.msc?