computer REFLASH fixed

My 1999 had a stalling problem and engine check light on problem , the dealer replaced the plugs boots and wires , a day later the engine light came on again and the engine stalled , going back to the dealer , they performed a computer reflash and it fixed everything , is this comon and what are or is a reflash of the computer?

My 2000 Galant LS ECU was reflashed when the service engine light kept coming on. The dealer replaced the spark plugs first but the misfire problem did not go away. After the reflash, the engine light came on once more. They blamed the problem on my Injen intake, never mind that it had been installed about two years earlier. The battery went bad soon after. I replaced the battery (with a Red Optima) and have not had any problems since June '04.