the reason they probably don't release it for XP is cause it's a complete change of the interface. that would probably be one extremely huge update if u ask me.
tdinc..... i don't even wanna comment on what you said, but i will anyway. Why on earth would any company take the time to make a new OS to that point.... just for it to be a fake. i mean, the entire installation process is changed, there's no more "Blue Screen" setup for when you format the drives, it only takes like 2 seconds to format a 30 Gig hard drive, etc... That would be the hugest waste of time ever. and if you have version 4051.... that's the one that they handed out at the one tech show, which i believe was kinda named Aero for some reason.... either way, there is no chance at all that any of the alpha builds are fake.