If you have a "Corporate Professional" version of XP, as I do, it never has
required validation by MS. The big users were not prepared to put up with
the nuisance of validation of every install so MS gave in and sold them a
special version. Somehow it has found its way, illegally no doubt, into the
hands of a lot of ordinary users.

Maybe MS doesn't care, but I suspect that if they could do easily it they
would prosecute.

The rest of your questions I will leave to the brains trust here.