If you checked everything like you said you did. Your board is either dead or the buttons on it are done. You probably need a new board.
I have to be honest though, I've never-in my 10 year span of playing paintball seen a dye board go down. Ever. So, double and triple check that all your connections are correct, none of the wires are crimped and that the battery is in fact good. Also, make sure the positive and negative prongs are in the correct position. Because if not you can fry your board.
Don't forget to check the manual!