It's a case of user-friendly fire when kid and computer launch a sneak attack of "WarGames" on the U.S. Department of Defense. It's a highly explosive new movie -- megatons of fun.

The computer is the WOPR (say whopper), the game is Global Thermonuclear War and the winning move is Armageddon. The challenger is a high-school computer whiz who, through chance and dogged detection, hooks into DOD's wargames computer at NORAD.

WOPR looks like a murderous furnace with digital eyes. He's a microchip off the old power bloc, anthropomorphic son of Hal, whose creator taught him not only to play hard but also to learn from his mistakes. But will he learn the ultimate moral truth before blowing the Soviets to smithereens?

Terrific teen stars Ally Sheedy ("Bad Boys") and Matthew Broderick ("Max Dugan Returns") are real and relaxed in "WarGames," only the second film for each of them. Sheedy plays Jennifer, the open, pretty pal of David Lightman, the boy who begins the countdown to World War III and becomes a man trying to stop it. Theirs is an easy-going relationship, not exploited sexually, and they grow to love and trust each other in their frantic 29-hour race to save the world.

The two are sharing an afterschool Tab when David gets into the WOPR's "back door" via the creator's secret password. "What shall we play?" it asks in measured synthetic tones. "Let's play Global Thermonuclear War," suggests David. At NORAD, where they aren't playing games, the video screens light up like Missile Command. It looks like the Russians are coming.

It's tense and full of suspense, with three separate climaxes -- and that's not counting a curt, tough opening chiller in a missile silo. Director John Badham ("Blue Thunder") is an action master with a conscience. Moving between the sterility of NORAD's Crystal Palace inside the Colorado mountains and David's home in scenic Seattle, he makes his point without begging the question.

"WarGames" is a soft-sell protest -- pro- people, anti-nuclear and anti-machine -- that entertains. It peddles neither the hysterics of Jane Fonda's "China Syndrome" nor the hopelessness of "Dr. Strangelove." It's a war cry for peace that's good to the last byte. WARGAMES -- At area theaters.