After you've done a proper secure wipe with a reputable product like DBAN then you need a CIA lab to get any useful data from it. The boys from Lagos won't bother. They will just move on to one that hasn't been properly wiped.
Oh and in answer to your original question, it is really really time consuming to uninstall everything except Windows and even then you need to clear out the registry... Better to let them worry about it not having an Operating System on it and use the tools above to clear it down completely.