doors not locking wit key fob?

Hi, I have a renault 1998 megane scenic monaco auto that will not open or unlock the door locks from the key fob - it has a sigma alarm/imm with key pad from new. The engine starts ok .there is no renault roof sensor for the fob either and i have put a new battery in the key fob .I have a reanult key number .i have tried puting the alarm code in the key pad too but no joy - any body help