you have picked the worst of the worse Operating Systems it seems.... unfortunately xp64bit may have been a **** test thing for the new 64bit apps that microsoft have forgotten about just now, as far as i know, they are probably investing more effort in getting support and divers for the vista 64bit, which as also ****....
i have been looking at the posts recently, and after reading horror stories, i'm not touching xp or vista 64bit for at least 2 years.
why bother with it? do you even have any 64bit applications? or do you have like 6gig ram or something?
i was very tempted to get 64bit in a new machine, to future proof it a bit, but jesus, after reading 20plus reasons not to i think i'll pay the extra 100 odd quid on upgrading to 64bit when there is good cause to, untill then why bother...
that has completely not answered your question, sorry. just needed to vent my frustration with annoying unanswerable questions that i myself have been asking about vista and xp 64bit............waste of time...