Help! 540i won't turn over

I bought a 95 540i this weekend. Drove it yesterday and today. Tonight I pulled the #1 spark plug to inspect it. It looked alright so I replaced it, put everything back together, but the engine won't turn over! I took it all apart and back twice to make sure I didn't screw something up. There are no messages on the dash. Am I missing something? HELP!

I've tried disconnecting the battery. All that did was reset my computer and the radio. I also read on a 5 series board that the engine codes can be displayed and reset by turning on the ignition and pressing the accelerator pedal a bunch of times. It didn't seem to do anything for me. No more ideas right now. Guess I'm walking to work tomorrow. :-)

Alright, how come nobody explained what the little unmarked black toggle switch on the console below the ASC switch does? After falling into bed exhausted, and defeated I recalled that I was absent mindedly flipping the switch back and forth earlier in the day. It didn't do anything so I didn't think twice about it. Needless to say after running outside to the garage at 2:00am in my PJs I flipped the switch and the engine fired right up. Live and learn.

As a first time BMW owner I am awed by this car. The engineering on the coils and plug wires is brilliant and unlike anything I've ever seen. I shifted into 'Sport' mode on the way home yesterday and the car changed from a sedate sedan into a snarling beast. AWESOME! I still have a lot to learn but I sure am enjoying each little discovery. This weekend I'm changing struts and brakes so I may be posting again really soon. Thanks for listening...

What was that switch for?man that blows Yeah I woulda been pissed
but oh well like ya said live and learn....

It's an engine kill switch. I think it's part of the factory security system. It looks stock anyway. The owners manual doesn't mention anything about it but it does say that information on the security system is in a separate manual that I didn't get with the car.

I feel for you as a mech we all been there, if it makes you feel better my first job customer complained of a THUMP in back of car well after a day of troubleshooting it turned out to be a bowling ball rolling around the trunk.How do you bil a customer for that?my boss just let me go on that to test my skill's..but ya learn right?Here a good tip,find a guy
named Dieter who was "terminated" by a BMW dealer and devolop
a repore with him about Germany and he WILL make you vedy vedy
happy......trust me..I know...ya da's is goot..