Does the engine turn over when you turn the key?

Did water get in the engine compartment? If so I highly recommend removing the intake to make sure there is no water hidden anywhere. Also, remove all sparkplugs and spin the engine by hand initially then with the starter. If any water comes out and the car sat for more then a month or so you probably have cylinder wall rust/erosion. This is not necessarily a death sentence but it can cause unequal compression between cylinders. I rebuilt a 350z engine due to this.

I do not flip "flood cars". I fix them and drive them. 2 so far. Still have them.
I have never tried to bring back a Mercedes. They have lots of switches and sensors.