[Al Skierkiewicz]

Joe covers most of the bases but if you still are having trouble try a small screwdriver handle (the insulated part) tapped lightly against the side of the ethernet connector on the Crio board. An over anxious student may have lifted the connector off the board. In general these are not easily repairable and certainly not for someone who doesn't do this on a daily basis.
Also be extra sure that the power connector is terminated properly. If you think it might be a problem, reterminate. I have seen more than ten teams who have had a small whisker of wire shorting out the power supply input to the Crio. Give it a tug test when you are done.