WAS DRIVING, AND WAS ABOUT TO MAKE A TURN, WHEN VEHICLE LOST POWER. DRIVER LOST CONTROL OF VEHICLE. APPLIED BRAKES TO STOP. HAD CHECKED VEHICLE & NOTICED PULLEY BELT HAD CAME OFF. TENSION BRACKET HAD FAILED (SERPENTINE BELT). ALSO, DRIVER'S SIDE AIR BAG DID NOT DEPLOY. *AK