Vauxhall meriva wont start after changing flat battery.the message safe is showing on dash board

Make sure ignition is switched on, hold down button AS and turn on the stereo. Wait for the beep, then release button AS. Display should now have 4 dashes ----. Enter correct code using the radio preset buttons 1 to 4. Once code is entered, press and hold down button AS again until code is either confirmed or denied. WARNING - you only have a max of 10 attempts to get it right, but if still no luck after the 8th attempt, STOP and contact a Vaux dealer.
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Car radio code calculator Decode Serial Digital mileage adjustment...