Changing the NIC means the system has undergone a hardware change, and the OP said he had done some stuff to hard drives as well, so the system determined enough had changed that it wanted to be reactivated. No big deal IMHO and most certainly not "absurd".

As for the EULA, it doesn't say the information has to be accurate, I think it has to be made clear that the request for information had NOTHING to do with the activation process.

Activating XP is an anonymous process and no information is required. The request for a name and number were made by the support department, to me it seems only reasonable that someone providing support over the phone knows a) who they are dealing with and b) who to call back if a call drops.

Providing this information to open a support case is the most normal thing in the world, but since it is Microsoft asking it I guess it is seen as the most terrible intrusion into someones private life and worthy of lawsuits.

I don't think any company will give tech support over the phone without at least knowing who they are dealing with. You can call yourself any name you want, but at least don't make those poor call center rep's life even more miserable by playing legal eagle on the phone with them, they are only there to help them. By not helping them with a simple request you invalidate IMHO the right to complain how long the call takes.