Stopping a Device after a Failed Start (Windows 98/Me)
On Windows 98/Me, the PnP manager issues an IRP_MN_STOP_DEVICE request without a preceding query when the drivers for a device fail an IRP_MN_START_DEVICE request. (On Windows 2000 and later, the PnP manager sends remove IRPs in this situation. See Understanding When Remove IRPs Are Issued.)
In response to the stop IRP, drivers release the device's hardware resources (such as its I/O ports), disable and deregister any user-mode interfaces, and fail any incoming I/O requests that require access to the device.