DO the locks all operate on the key? I know my remote is almost disfunctional i.e. you need to put the fob on the windscreen to get it to function, but it works on the key. Are the batteries in the fob of a decent make, i.e. not something from a pound store for instance! It might well be that the fob is at fault as these tend to live hard lives, in pockets, chucked onto tables etc. The fob would be the place where I would start esp if the key operates the locks OK.