A computer-implemented system for process control has two operating modes: normal mode and active procedure mode, with automatic transition between them. In normal mode, the operating system, firewall and anti-virus are fully operational. When entering a time-critical phase of a process, a process control application signals the operating system and utilities, whereupon transition to active procedure mode automatically occurs, in which access by the system services and by other applications to the resources of the computer is selectively limited in favor of the process control application. Upon completion of the procedure, the system automatically returns to normal mode.