A mechanism is provided for enabling an auxiliary program to be executed in a computer system, after an operating system has been loaded and executed, without rebooting the computer system. This may be achieved by suspending execution of the operating system, executing the auxiliary program while execution of the operating system is suspended, and then resuming execution of the operating system. In suspending execution of the operating system, state information defining a current state of the computer system is saved. In resuming execution of the operating system, the saved state information is used to restore the computer system to the current state. No state information or data should be lost as a result of suspending and resuming execution of the operating system. From the viewpoint of the operating system and the applications (if any) executing within the environment provided by the operating system, execution of the auxiliary program is transparent.