I have a 2013 Optima with about 65 k miles on it. It's been pretty reliable and ran smoothly until yesterday when it wouldn't start. The brake pedal wouldn't go down (I've had that problem before but it was fixed under warranty last year). When I just pushed the start button, I hear a few seconds of quick clicks, then nothing. My mechanic (who I trust) said the main computer motherboard shorted out and is shorting out all the systems, like the alternator and the battery. It'll cost about $1500 to replace everything. Has anyone else run into this problem?