The article claims that "this option lets you completely and nondestructively rebuild, repair, or refresh an existing XP installation while leaving already-installed software alone (no reinstallation needed!)."
Screen Twelve of this walkthrough shows that you enter a product key, which should resolve the O/S-laundering scheme you seek.
As always, there is no guarantee, so you should back up your important data.
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I would look into a repair installation as described above.
For detailed instructions with screenshots, check out the article, Langa Letter: XP's No-Reformat, Nondestructive Total-Rebuild Option.
The article claims that "this option lets you completely and nondestructively rebuild, repair, or refresh an existing XP installation while leaving already-installed software alone (no reinstallation needed!)."
Screen Twelve of this walkthrough shows that you enter a product key, which should resolve the O/S-laundering scheme you seek.
As always, there is no guarantee, so you should back up your important data.