Firstly, the USB Device [in your case a CD-ROM] is contained within a USB
caddy of some description. This will be the first item that is identified in
the plug and play sequence.
There may be a specific driver required for this item.
Secondly, a CD-ROM will be made by some manufacturer and have a model number
on it, so you can look up their website and download an XP driver for it. Be
aware that there is not a specific USB driver as opposed to an IDE driver for
the CD ROM: it is just a Windows XP driver for the device. The USB drive as
mentioned is associated with ther Cradle for the CD ROM which attaches via
the USB cable.