hi, i know this question kinda dump but i been using a vista evaluation copy with a genuine key, i don't know if it will expires or not because if doesnt then that mean i get window vista for free ? well even so i guess microsoft wont let me update then?

huh Microsoft sends you a Vista key when you sign up for the Beta/Evaluation, if you mean this key then it will still expire.
If you own vista and have official key y? not install the full one.

I don't think its possible to use an XP key.

please give more details

i had a Vista RC2 key from microsoft. I been using this key for windows vista ultimate and just wondering if it expires,i knew it will , well, do you know when it will expires since windows vista already offcially came out today?.