While using my Openspot3, it just went dead. Power light went out, wifi connection was, of course, lost. The unit was plugged into my pc to top off its charge (since it's been awhile since I used it) - and it was showing that it was charging. Then all of a sudden - nothing! Now when I connect it to power, the green power light comes on only for a brief second and then goes out. Nothing happens when I push the power button. Could it be a battery issue? Is it replaceable? Or does it sound like something much worse?