Upgrade Vista from 32 bit to 64 bit

[leatherneck1954]

OK so suppose you have Vista Ultimate 32 bit installed on the pc and decide later that you want to run Ultimate 64 bit. This is with a i7 CPU so it should work 64 bit hardware wise.
Do you wipe the HD clean and load the new 64 bit version?
Or can you install the 64 bit version over the top of the 32 bit version?

 

[notherdude]

Fresh install is your only option. 32 will not upgrade to 64.