On several occasions I would find that my mazda 323F would not start. The starter would not even turn over and my lights would work as normal. I dont think it was a flat battery due to the lights working. Attached jump leads and it started first time. Once started you can turn off the engine and then it will start no problem. I had the battery checked out and it is ok. I now carry a jumpstart box from Halfords as I do not know when it will happen and I cant see any obvious reason.