Win 9X Dial-Up Client & Control Panel Configurations

Control Panel: Modems Section & Device Manager

You generally want to do your modem configuration in the dial-up properties. You would go to the modem section of the control panel to reinstall a modem and/or remove "ghost" modems that aren't actually installed even though the computer thinks that they are installed.

Don't bother configuring the modem's properties in the screen below. The dial-up properties will override these settings. Just add or remove modems as needed.