Remote control battery change- can't get remote to sync with alarm

[JDMils]

I've successfully replaced the battery in my SAAB 900 (94 model) remote using the Changing remote battery thread and I have the remote in post #4 but I can't get the remote to be recognised by the car. What's the procedure?

I cannot even start the car as the alarm is ON and keeps sounding each time I open the doors and the starter is bypassed.

[Oscuro]

Couple of things to try:
1. Press the unlock button 5 times in a row to re-sync the fob with the car.
2. Does the LED light on the fob light up when pressing the button? If not, double-check that the batteries are installed correctly and the contacts are free of corrosion.