how can i fix the central locking and immobiliser on my renault laguna?

How can I fix the central locking and immobiliser on my 5door t reg renault laguna? Remote locked it one day when the boot wasn't properly closed and since then remote locking no longer works and can only actually lock my car by sitting inside it with all the doors closed and pressing the central lock button (which locks everything from the rear doors backwards) then jumping out and using the key to lock the 2 front doors - far too much hassel!car starts with no problems so don't actually want to disable it