The invention virtualizes a computer that includes a host computer system, which comprises a processor, memory, and physical system devices. A conventional operating system (referred to below as the “host operating system” or “HOS”) is installed on the hardware. A computer program product that is executable within the host computer system comprises computer-executable code for implementing an interface software layer, preferably a virtual machine monitor, between the host system and a virtual machine; for reading in and storing state information of the processor associated with the HOS; and for logically decoupling the HOS from the processor with respect to pre-determined functions of the interface software layer and the virtual machine by setting the processor state information to settings associated with the interface software layer.