Enabling Username/Password Login for Multiple Users on a Macintosh

To password protect a Macintosh running OS X:

1. Go to the Apple menu, choose System Preferences and click on the "Accounts" icon.
   
2. In the new window that opens, first make sure that you have all the users created that will be using the machine. Use the + or New User button to create new users as needed.
   
3. Make sure that "Log in automatically as ----" is NOT checked for any of the accounts listed.
   
4. Go to the "Login Options" tab and set it to display the login window as "Name and password".
   
5. After making these changes, close the windows (making sure to Save Changes if prompted) and restart the computer. After restarting, you should be prompted for a username and password.

To password protect a Macintosh running OS 9

1. Go to the Apple menu, choose Control Panels and select "Multiple Users".
   
2. In the new window that opens, make sure the radio button at the bottom indicates that "Multiple User Accounts" is turned ON. Use the New User button to create new users for the machine as needed.
   
3. Once the needed users are created, hit the Options button. Go to the "Other" tab in the Options window and set the radio button so that users type their names, and that the user account will be from "Multiple User Accounts". Set the other options on the tabs in this window and close the windows, making sure to save all changes if prompted.