I have a Arduino UNO and the on-board Led connected to pin 13 refuses to light up anymore. I also am not able to get anything from pin 13, its a dead pin. All I had was the simple blink sketch on.
At any point did you have anything connected to pin 13?
No, nothing was connected, I am planning on returning it now.
If you never connected anything to Pin 13, and you only used the un-touched "Blink Example"... then something is missing here. It is unlikely Pin 13 stopped working suddenly. It is more likely you have changed some code or you using Pin 13 (even accidentally.)
If you use an external resistor-LED and blink 12 does that work? Same for 13 or not??