make sure thats in the original package unopened.
if he used the serial number to register windows, you might not be able to use it again.
Your pc will lock after i think is 30 days if you don't register windows.
you are thinking of activating, not registering. You don't even need to register your ownership of windows but you do need to activate.
You mean that if the seller gives the registration # or code that came with the solftware i won't be able to install it?