Is it a 2 button remote without an led?

If it is then try this...

1. remove the battery (in the remote)
2. press the buttons one after the other
3. replace the battery
4. stand by the car (with the door locked) and press the lock then the unlock button over and over again untill the door unlocks.


It might take a while - but usually works.
We change the batteries for customers at work - this has got me out of the sh*t many many times!!