I'm not sure if this is the right area to post this but there is an error in one of the examples delivered with the IDE. The EEPROM_Clear sample has code to clear the EEPROM contents and the comments say it will turn on the on-board LED when done. The code is missing the pinMode(13, OUTPUT) statement that allows the LED to be turned on. Small issue but confusing to a newcomer.
I have submitted a patch for this issue to the Arduino IDE repository: eeprom_clear example: Set pinMode of LED pin by per1234 · Pull Request #4213 · arduino/Arduino · GitHub
The crazy thing is this was reported Sep 28, 2012 but was never fixed.
My patch has been accepted and will be in the next release of the Arduino IDE and the hourly build. Thank you for reporting this issue!