Windows 2000 doesn't include any Windows Genuine Activation, but with Active-X, Microsoft can check the license of Windows 2000 that is invalid or not. There is no meaning to activate windows 2000.
You only have to switch the CD to the VL channel by editing a text file and it won't need a key at all. Then I wonder how M$ could check if it's legit or not...
ok, and what about xp, which is no suppuorted now, the same? or there the activation is the same as always?