A Key Issue

 I  turned the key in the lock and the car started ok but the key distintegrated in my hand and was left dangling in pieces. I left it hanging and drove to Evie's house in case there was more trouble.  There was more trouble, as when I turned off the car, I thought I could just use the shaft of the key to restart as it.  No such luck.  I thought I collected all the pieces.  Debbie put it back together and sticky taped it but still no restart.  This car is newly fitted with two child seats and has been set up to bring them back from the hospital and we have been told it must be towed to a Toyota dealer for reprogramming a new key and this is the weekend so at best it could be done on Monday.   I went back three times to search the car and each time I found more parts.  The key consists of nine separate parts all unconnected.  There is the key barrel, two halves of the casing, two rubber buttons, a soft rubber overlay, the circuit board, the button battery and a blue innocuous plastic piece with a particular shape.  Whatever that thing does it has to be inside the key. I spied a shaped compartment that looked very sinilar to the blue block shape and when that was put in place, yes the key worked and restarted the car.