In all my years building, i've not known shorts to cause extreme heat situations, but that's not to say your thought process has no merit. If the CPU is overheating, that would certainly explain (among other reasons) why you don't have a display.
I'm assuming that you remembered to install the heatsink and fan.
Remove the heatsink and check to see that the thermal pasted has been applied in smooth thin coating. Too much thermal paste will trap the heat in the CPU, thus making the heatsink redundant.