A network-attachable computer system (40) that comprises a network interface for connection to a network (41), a server module address, a secure identifier (ID), and a key k. The computer system (40) generates identity information which comprises the secure identifier ID and which is protected using said key k. This identity information is automatically sent via the network interface to a server module (42) which is reachable via the network (41) by using said server module address where it is used to determine whether the respective computer system (40) is reported lost or stolen.