Unless your machine remains physically identical to the original installation - or darn close to it - you're old key is not going to work. Once you re-install XP you'll type in your activation key, it will "phone home" and find that the key has already been installed. You'll be prompted to call Microsoft on a toll free number and give the service rep a 49 digit number to which they'll supply one back.
It's a really simple process and I've never had to wait more than a minute on hold. They'll ask you why you're re-installing to which they've accepted every reasonable answer I've given them.
Hello,
How-to save old key (xp home) and put new key (xp pro full version not upgrade version) when doing upgrade OS? Do I have all my data and all patches preserved or scraped. Thanks for help.
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