as my rig is "home made" with a purchased OEM (Home premium 32 bits) will its serial key be valid on a Home premium 64 bits clean install ? I suspect "crosoft will require at least a telephone validation which should the be rejected as the key is already in use.
Dude you are getting annoying asking the same question over and over, keys are architecture independent and are just locked to edition (starter, home basic, home premium, professional, ultimate) all these answers could have been found in the the stickies... spend some time reading them!