help activation windows xp

i tried plugin my old hard drive up other day to get data from it but its sayin i need to activate it .
how i go about doing that? i have no codes or nothing cuz it was already activated when it came with my old computer.
Answer #1
Download a crack from here and activate it.
Answer #2
i just need a activation code to enter
Answer #3
can any1 help me ??