My car was running fine, then due to being unused for a while the battery went flat. I jumped started it and run round in it for a day and it was fine. To make sure the battery had a decent charge in it, I removed it and gave it a good charge. When I put the battery back on it wouldn't start... It turns over fine but wont fire up. I checked the fuel pump relay and fuse and they're fine. An auto-electrician has looked at it and was convinced it was the transponder reader. He's replaced that and it's still not right. If the battery is disconnected then reconnected it will start. If you turn