trouble with Windows XP: Validation please help me

i have problem,
i plug up my old hdd
log in
sais i need to activate windows
i eint got a code or anything
and i eint got a start menu so i cant access anything
just the activation window, when i close that it logs me out.
help someone plz i need data of it !
Answer #1
i guess the bios settings of ur old hdd are gone…..m not sure but if u dont have data in :/c…..then try doin a fresh install…..maybe win7….installs in 30 minutes and recover ur data
Answer #2
i just took my computer to get repaird they give me a new hdd
maybe they got the old windows key from my old hdd and put that into the new hdd?
ther must be data on it because it still has my username on login screen