Sometimes on initial 1st boot up when the computer is turned on for the very first time, it can give you the option to create a recovery CD.
If the laptop does not come with this feature or does not come with the recovery CD, I would not buy it.
Reasons being that you can download WITH hassle another windows CD, but it does not have the specific drivers that you need for your laptop as each laptop has different hardware components. Also, how do you get the preloaded software that came with the laptop .... fact is, you dont.
Also, do you really want the hassle of surfing the web for a CD and then also going through the hassle of looking for the product ID ?
It is not worth the effort !
Bear in mind, everyone at some stage of their life has to reload a laptop !