[Al Skierkiewicz]

dex,
While the Crio is pretty bullet proof it is not indestructible. The first things to check is the +_24 volt LED on the PD. Is it lit and steady? If not, remove the connector from the PD and turn the robot on. If the LED is still not on and steady, the fault lies with the PD. If everything is OK, then, using a voltmeter, check the +24 volt input to the Crio for presence and polarity. Examine both ends for stray strands of wire. It is quite common for strands to wander and short to the other wire. If all of these test pass, then with power off, remove all of the modules and check for shavings, bent pins, or other obvious damage to the chassis. Power up with the modules removed and see if the Crio will start. If it does, turn it off, add one module and try again. You may have a bad module.
We are all assuming you have a known good, charged battery on the robot.
Let us know how things are going.