Which XP Version to use

[justinmypants]

I am building my first computer and am unsure as to which version of windows XP to get. While most of the parts are brand new, I will be canibaizing my current computer for its 2 hard drives. Now because the current computer is from Dell it came with an OEM XP, which I think means that it cannot be transferred to another machine. I also no longer have the XP CD that the computer came with.

I'm pretty sure that I need XP Pro because the the CPU is going to be a dual core processor, and I understand that XP Home does not support dual core or multiple processors (i think). But do I need Full or Upgrade? Full says that it requires a computer with no OS or a much older version of windows. But would I be able to upgrade the OEM version that I have?

I hope what I said makes sense. Thanks for your help.

Edit:
I also plan to reformat the hard drive.

 

[Defence]

Actually, I not exactly understand what do you want.
I use WinXP Pro, as for OEM XP, I think it couldn't be upgrade to XP Pro. But why you should transfer OEM XP? If you want only it, you may create clone of OS partition.
But if you want to use only XP Pro you need original bootable XP CD.