Do I need 64bit Win XP for a dual core 64 bit CPU?

I didn't even think of it when I ordered my new system. I currently have the same copy of windows xp home I've had all along. Do I need to get 64 bit XP professional for my Athlon 64 X2 dual core processor to work? I'd hate to have to have to buy a retail copy.. argh
Thanks

No. 64 bit in hardware just means that it is capable of running 64 bit software but will run 32 bit just as well.

However in moving XP you will lose it on the older machine. One key = one machine. You will have to phone Microsoft in order to activate and they will switch motherboard ID's for your Product Key.