Example embodiments of the present invention relate to a system, apparatus and methods for preserving the integrity of a code to prevent it from being modified, maliciously or inadvertently, while it is in execution in the RAM of a computer platform. This method also may be referred to as code hardening. Code to be hardened in example embodiments of the present invention may be referred to as protected code. Example embodiments of the present invention are able to externally detect unauthorized stoppage of the hypervisor by employing (1) a launch-time metric of the protected code; (2) a run-time metric of the protected code; and (3) a liveliness indicator of the protected code.