Faulty central locking on W reg ford focus?

The remote central locking has stopped working on my car? My drivers door will open with the key, the front passenger door won't open from the inside or outside, the offside rear door won't open from the inside or the outside but the nearside rear door will unlock from the inside only. The boot will open with the key but not with the button on the dashboard. I have put a new battery in the keyfob but this has made no difference