BMW Repair: 1998 bmw 740 i, 1998 bmw 740, starter wire

Question
I have a 740i bmw 1998 My problem is I it will not crank. It was riding fine all day made about 6 stops this day and then at last stop the car would not start. I tried replacing the battery even thought the power to the lighting seamed fine. I also tried to use another key nothing there however I left it for 15 to 20 mins and it started now would you what the problem is

Answer
checking the wires for a good connection at the starter wire that goes to the solenoid for power is where you should start.It is the smaller wire (black w/yellow stripe).Making sure the connection is clean and tight.Also check the body ground wires for corrosion(sometimes the braided line will look green in color)