Everyone should know that any hardware changes prompt the game to re-activate and there is a limit per key for activations. Uninstalling does not revoke the key. OS changes will also trigger the need for a re-activation. So basically if you change hardware or reinstall ~5 times you will now need to get the key unlocked or a new one issued - to which GSC and Valve keep referring you to the other with neither company doing anything to resolve it.
Read more over here.
Petition to remove activations based DRM from Stalker Clear Sky
Posted on Sunday, Sep 21 2008 @ 21:51 CEST by Thomas De Maesschalck