I've used longhorn before..... like 5 months or something? I think it was like version 3669 or something. Well it was pretty crappy then, and today im like "damn im gonn come back to this forum and see what's new and if things have changed"

Well i came back, and now i hear there is a 4015. I have a few questions:
1.how much better is it than the one i used like 5 months ago?
2. is it possible to get a new install? or upgrade?
3. Where are the cd keys
4. any tutorials or things i need to know to make it good?
oh yea and right now im on xp pro
THANK YOU VERY MUCHY FOR YOUR TIME