For years, Walt Disney Studios has had a foolproof way to pick up extra money, especially around the holidays: It simply re-releases an old classic and sells tickets to a whole new generation of kids. Well, Disney's about to try the trick again, but with a far different film. On Oct. 6, the studio will re-release "Tron," which opened only 10 weeks ago and is just now officially closing. The computer thriller didn't fare too well its first time around, despite high hopes -- and a hefty financial investment -- on the part of the Disney folks, who figured this would be the film to win them a new audience and redeem the studio's poor track record with recent releases. "Tron," though, opened to fair business, dropped 50 percent its second week, fell almost that much again its third week, and limped through the rest of its disappointing run. Hardly the stuff of which reissues are made--except that as the film was dying, the video game Tron was becoming the No. 1 arcade attraction in the country. Disney isn't explaining exactly why it's re-releasing "Tron" so quickly -- besides saying it will emphasize "college towns" this time around -- but it's clear the studio is banking on the success of the video game (actually, several games in one, all of them loosely -- sometimes very loosely -- based on incidents in the movie). In July, Disney hoped that kids would leave their Pac-Man games to go see "Tron"; in October, they'll hold their breath and see if anyone's ready to leave his Tron game to catch the movie. After all, you can see the film for the cost of a mere 20 games at the arcade.