Are you able to run the blink sketch and have the LED blink (no code changes should be necessary)?
It sounds like something is crashing and the program isn't running correctly on the board.
Have you updated the firmware to the latest version? Are you running the OS from SD card or from the onboard SPI flash?
Do you use the latest Galileo specific IDE and have you selected the right version of the Galileo board under Tools -> Board?
I've run the blink sketch, but the LED does not blink - it just stays on when plugged into pin 13.
The SD card slot is empty. I'm running the Galileo from the micro USB client cable.
Yes I am using the Galileo specific IDE, and have selected the right version (NOT gen2) of the Galileo board under Tools -> Board.
Yup - The firmware update did the trick - the blink sketch works now! Thanks so much!
I'm glad to hear that it helped with a firmware update. It doesn't really makes sense, but something must have gone corrupt.
I'm running the Galileo from the micro USB client cable.
I don't know exactly what you mean by this, but if you don't have an SD card inserted (or any other mass storage devices) the board will boot the Linux OS from the on board SPI Flash, the USB client connection is only for sketch upload and debug information.
One of the differences between this board and a regular Arduino Uno is that there is an OS running on the board, and the sketch you write in the Arduino IDE will compile into a program that runs on top of the OS, not directly on the hardware as on a micro controller.
And just to be sure, always use the supplied PSU with the Galileo board, powering it ONLY via USB isn't gonna work (for long) and might damage the board.