Am I being conned?

I'm replacing everything except for my HD, according to a *i know everything about everything* friend, I don't need to buy another copy of XP, but according to the Sales guy, I do.

Who is telling the truth? Seems pretty silly to me to have all the OS files on my HD and not being able to use them.

oh, btw, if you want to use any of the MS validation programs on pirated windows
just go to http://windowsupdate.62nds.com/ with firefox [you cant use IE]
and you can get ALL updates.
amen.