Four Two, you said:
As long as it's only installed on one PC (and possibly a laptop, but I'm not to sure about that) then just get it revalidated. You can buy a new PC and still go ahead and use your copy of XP. Time and time again
Are you sure that is correct with regards to a new PC? My understanding is that on your original PC yes, but a new one requires a new licence.
In fact if you were to replace too many components of your original PC you could trigger a requirement to reactivate your version of XP.