Windows 98 wasn't designed for that type of security.  Microsoft
assumed, rightly or not, that it's used in a home environment where
everyone is trusted.

If you want to keep unauthorized users off your computer, set up a
BIOS password that has to be entered to boot the computer.

Here are some possible ways to prevent users from bypassing the
Windows logon.  However, it's not hard to get around these, and
information on how to do it is freely available on the web:

1. When the logon is canceled, Windows actually logs the user on as
the "default" user.  You can configure the default user to be
immediately logged off, causing the logon prompt to return:

  http://registry.winguides.com/display.php?629

2. Doug Knox has developed a procedure that requires a valid logon:

  http://www.dougknox.com

Click "Security" and then click "Prevent Unauthorized Users from
accessing your computer".  Be sure to follow the steps exactly as
documented.

Done not in Windows but the BIOS (before Windows loads.)
1.  Interrupt startup checks with the key identified on
screen (probably DEL or F8.)
2.  Locate PASSWORD in the array of menus,
probably under / Boot / Security.
3.  Choose a memorable  password, enter it, and
follow the prompts to save and exit.

The BIOS battery will preserve the password.
At next boot the PW must be entered from the
keyboard in order to start the PC.

You can chk Start/Settings/CntrlPnl/Users to see if this will help

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