WarGames (1983)

David Lightman (Matthew Broderick) is a young computer whizz who hacks into what he believes is a new line of video games, little knowing that it is in fact NORAD, America's defence program. He inadvertently creates a hostile global situation, placing the world on the brink of nuclear war. Together with his girlfriend Jennifer (Ally Sheedy) and a misanthropic computer expert (John Wood), David must fight to prevent an atomic meltdown.