Hi I have 2 questions regarding an upgrade installation of vista Ultimate.

1) i have a amd 64-4200 cpu, with 1gig of ram and a 1gig usb pen drive for
ready boost, woudl it be best for me to stick to 32-bit for the moment or
urgarde to 64-bit, since ive had this cpu for over a year it would be nice to
start using it at its full capability but is 64-bit worth it and are there
any pros and cons to this?

2) Once ive upgarded my version of xp pro to vista, would i then be able to
install that copy of xp on a laptop as i have one at the moment but it doesnt
have any os on it, or would this invalidate my upgrade to vista?

ty for any help or comments

Danny