on the back of the door locks if we are on about an escos there should be a round thing that sits round the doorlock with wires coming off so when you turn key in door it spins this thing to turn std alarm off (the alarm may not be in use but this might be the prob). i had the same trouble with my car when i did the new locks i hadnt put this thing back on it was just hanging in the door and it was set so when i turned the key it did nowt cos it was not on the lock, i put it bk on and prob solved