What interface is used to manage the configuration of a legacy non-Plug-and-Play device after installation?

The Device Manager is the correct interface used for managing the configuration of a legacy non-Plug-and-Play device after installation. This tool allows users to view and manage all the devices installed on a computer, including those that do not support Plug-and-Play, which typically do not automatically configure themselves when installed.

In Device Manager, users can modify device settings, update drivers, and troubleshoot issues related to hardware components. This is especially important for legacy devices that require manual intervention to configure parameters such as IRQ (Interrupt Request) settings or memory addresses, which are commonly managed through the Device Manager's properties settings.

The Control Panel, while also a management interface for various system settings, does not specifically offer the same level of detailed device management as Device Manager. System Configuration is primarily used for managing startup options and services rather than hardware devices, and Task Manager focuses on currently running processes and performance monitoring rather than device configuration. Therefore, for the purpose of configuring legacy non-Plug-and-Play devices, Device Manager is the most appropriate choice.