An RF tag has an enable/disable circuit connected to a critical part of an electronic object/circuit, e.g. a computer mother board. The critical part of the circuit is any circuit component and/or connection that can enable and/or disable the electric circuit operation. Signals are sent to the tag to change data in the tag memory which causes the enable/disable tag circuit to control the critical part to enable and disable the electric circuit. A system checks the status of the tag, e.g. the electronic circuit was paid for, before enabling the electronic circuit.