I uploaded "blink" so it is not the sketch. And I observed the same.
I disconnected the arduino from my hardware and "blink" startet as soon I connected the power. So it must be the hardware I conected.
My hadware consists of some bottons with 10K pull up resistors, MOSFETS on the PWM pins with RGB LEDS and some potiometers on the Analog in pins. I also use the V in pin to power the MOSFETS
PIN 13, 0, 1 are not connected.
When I connect the board to the 12V input the "on" LED os on and the L LED is also continously on but no so bright as it used to be.
Any clue?