Currently I have a computer with windows xp 32 bit installed. I am getting a new computer and I was wondering if I can upgrade to windows 7 64 bit on my current computer then move the hd to the new one. (The new computer doesnt have the same motherboard or cpu) Just want to know if I should do a clean whip now and upgrade or do a clean install when I get the new computer with the new mother board.
The install will become invalid (and likely just outright wont work) when moving to the new rig because of the different hardware. Also if you get an OEM copy of Windows, you only can use that product key on one motherboard. So if you do it on your old system, you will need to buy a new key for it to be valid on the new system.
Do a clean install on the new rig.