Access protection system and method for computer systems

The computer system initially operates in a fully operational mode in which an operating system in the computer system is operating and the computer system executes one or more user applications installed in the computer system. In response to a predefined time interval lapsing, the computer system automatically switches from the fully operational mode to a limited operational mode in which the one or more user applications are terminated, the operating system is shut down, and a BIOS within the computer system solicits entry of a password by a user. If the user fails to enter a valid password, operation of the operating system and execution of the one or more user applications are prevented. If a user attempts to activate the computer system for which the time interval has already lapsed, a BIOS within the computer system boots up, determines that the computer system is currently set for a limited operational mode, prevents boot up of an operating system of the computer system, and solicits a password from a user. If the user fails to enter a valid password, the BIOS continues to prevent boot up of the operating system. If the user enters a valid password, the operating system boots up and executes one or more user applications within the computer system.