If this is true, this would be a better ways, because I know of some companies (and my school) who use PIDs with -640- or something else in the middle and this would be a better way of blocking unlicensed users! lol! Your school is unlicensed? Tut, tut... lol Maybe you could use that to you're advantage.. Chris! No, they're not unlicensed... PIDs aren't only the middle three digits (ie. -640-)... They consist of most numbers, and some of the PIDs with specific numbers including -640- were already blocked in SP1... This doesn't mean that all copies of Windows XP with -640- were blocked... Well.. I think 640's are being blocked in sp2.. Because there pirated. Well thats what i've been told! Chris. Incorrect. You've got the situation reversed.