Windows Seriel Number Question

If you have two computers on the same network and you try to install xp pro on one and you use the same seriel as you used on the other one on the network and it's not a legit copy will windows see it and mess up? Also I don't endorse pirate copies of windows. This is a hypothetical.

>>9
For there being such a shitload of keygens around, it's amazing I can't find a single one.

Um, sorry, my mistake; I thought you meant lots of **working** keygens, not ones that make windows update fail or which don't work outright.