I have a 2000 BMW Z3 that has sat for about a year. I started it periodically and it always started right up. I went to start it one time and the battery was dead. I charged the battery and tried again. The engine turned over but the engine would not start. Any ideas why?

Hi,
I think that if the battery went completely flat the vehicle may have lost the security code, or the same can have happened if you did not follow the boost charge instructions when starting. If that has happened you'll need to have the unit re-encoded by a dealer. Keep in mind that starting a vehicle periodically is good but if you don't run it as well the battery will become exhausted and finally fail. The start up of any engine drains more power from the battery than any other operation. You need to start it and give it a run.
Regards Johngee10