Most laptop microphones (the one builtin) are not suited to speech recognition. So Dragon should install just fine (if not ask Dragon why) and then you upgrade to a decent microphone.
When I got my new Fujisu Amilo PA1510 Media Center Edition 2004 laptop this year I didn't know there wasn't any speech recognition software that would work with it; I thought all XP was basically the same. As I am disabled I rely on Dragon but I couldn't use it on my laptop, at least not Dragon 7. All Fujitsu Siemens could suggest was to change the system to Home Edition. If anyone has a better idea I would be very grateful