It was running fine, just quit and will not restart. any suggestions on what and where I should start looking?

it had been driven, when I parked it , it would not start.

there is a lot of information missing from this post.

we dont know whether its fuel, spark or battery related. you havent described any symptoms, anomalies, observations. for all i know this car is not in park or neutral.

you need to tell us if you can hear the fuel pumps engage when you turn the key to position 1.
if the lights work fine and the horn sounds normal
if the car cranks but doesnt start.
if the car doesnt crank


et etc etc

its rather silly to not do your due diligence and come here for help.

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'O=00=O'
bmw 2002.
long live the legend