I think its just written in a misleading way ,they meant to say : DEP (data execution prevention), UAC (user account control), and PMIE (Protected Mode IE) - that don't exist in Windows XP. it does not say DEP is not in windows XP . the comma between each section seperates them . for example windows 7 is great it has loads of better features ,and PMIE that xp does not have . the auther could have been clearer , As we all know xp does have DEP. INCIDENTALLY dep ,UAC ,security centre ,windows firewall ,are all disabled on my machine . 3rd party does it better and with less invasiveness.