I'm pretty sure I've read some place (probably here) that regardless of version (KMS / non-KMS) the system isn't permanently activated, and will work for 180 days and try to re-validate the activation every 30 days. Could someone please confirm or deny this with a link? I could swear it was somewhere in the stickied OEM thread, but I may be delirious at this point. Or perhaps I just got that impression after reading that OEM activations may be invalidated...