1. Make sure the car is in a safe and flat location, with the parking brake engaged.
2. Try to start the car normally by turning the ignition key to the "ON" position. If the car does not start, continue to the next step.
3. Shift the gear selector to the "N" (neutral) position.
4. While holding the gear selector in the "N" position, turn the ignition key to the "ON" position.
5. Release the gear selector and press the "Start" button.
6. If the car still does not start, try pressing the "Reset" button located on the center console.
These steps should help you restart your BMW 530i in most cases. However, if the problem persists, it is advisable to have the car checked by a qualified mechanic or take it to a BMW dealership for further diagnostics and repairs.