Upgrade from Xp Home to XP Pro

I am inheriting a machine that has XP Home. My old machine, which I will be
putting out of service, has XP pro. How do I put XP pro onto the inherited
machine? Will it upgrade if I insert the XP Pro disk and run the install
program or must I reformat the hard drive on the inherited machine?

Assuming you have a "Retail Version" of Windows XP Professional,
and not an "OEM Version", start the computer and when you arrive
at the desktop, insert your Windows XP Professional CD in the CD
drive and select "Upgrade".

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Carey Frisch
Microsoft MVP - Windows Client