How are you powering your board? According to your description it sounds like the board might be having powering issues?
We could determine it, if you have a serial cable, could you try to connect to the board's terminal?
What do you see? Is the board rebooting itself?
I'm powering it with a 12V power supply. Good idea about the serial cable. I think I have one. I'll give it a try.
Yes, give it a try and let us know if you notice any strange behavior.