Two problems related to battery dead have been reported for the 2007 BMW 3 Series. The most recently reported issues are listed below.
Red electric steering wheel lock icon on screen and car will not start or turn over. Radio works and everything else but car will not start. When battery died, and I charged it full, then went to start the car and this red electric steering wheel lock came on. Had to get car serviced.
Battery died. Jumpstarted, drove for a bit. Turned off, turned back on drove home. Parked the car. Tried to restart and the red electronic steering wheel lock indicator was on. Plenty of juice in the battery, car will not even attempt to turn over. Can not get into neutral to tow out. Car is dead where it sits because of the electronic steering lock. Thank goodness we weren't in the middle of nowhere.