Hi please can you help with my central locking

hi i have had the same problem, the things is your key has lost its coding to your car, is it the diamond shpe key with a open, lock and open boot on it if it is you can get in your car turn the ignition to the point before the engine starts,
take the key back out,
hold the unlock button,
whilst holding the unlock button press the lock button three times,
let go off all buttons then the locks should bounce to say the car key has recoded its self,

hope this helps cheers