I expect it will do both, Although updating from Vista is supposed to be pretty easy.
(
2 Can Chunder Word to your mums, I came to prod bums,
Wed 21 Oct 2009, 19:00,
archived)
When I upgraded from Vista to an RTM copy,it actually didn't change the boring vista boot up screen with the snazzy new Windows 7 one :(
( B.T.,
Wed 21 Oct 2009, 19:24,
archived)