Mercedes Benz C300 Sport won't start

C Class will not start in a parking garage. I wasted
my time waiting a Road Side Assistant who
showed up in an Escalade. I left the car overnight
and brought a friend who knows a few things
about cars.  He disconnected the battery to reset
the computer and the car will not start.

I read a lot of the suggestions here and the one
that did the trick was setting off the alarm, putting
the key in the ignition and turning the steering
wheel. Almost 24 hours later, the car started. I am
holding my breath.