How to make Oracle 7.3 on NT auto start?

My oracle server on NT 3.51 starts when the machine boots, but if I go into svrmgr23, it says "Connected to an idle instance" If I type "startup", it successfully mounts the database. How can I get it to do this when the system boots - this is too much for the users to handle. Thanks
Joe Received on Mon Jan 19 1998 - 00:00:00 CST