No radio, clock, power windows or locks??
I believe they share a fuse in the fuse box near the dash.
Some Hyundai models have a little black connector in the dash fuse box. (be careful of orientation)
It is used to put the vehicle in travel mode as to save the battery on those long ocean voyages to market.
That could have come loose??

 

Great thought on that connector. Just pulled it out carefully and reinstalled no change.

 

When it comes to electrical problems especially power supplied, you need a diagram to follow . That will save a lot of time and trouble.
It can be done the hard way and that is to start at the source and physically trace the wiring from source to the system or component.Power can be verified to the point where it is lost. Jumping around just wastes a lot of time and effort and can get expensive replacing good parts. Not knowing your level of expertise , this may be something best left to a more experienced person.

 

Does check engine light turn on when key is first turned to the on position?
If no check engine light then ECU is not being powered up?
The way the failure began, I would be looking for wiring issues, frays and broken wires
Even look at fuse box for green crusties.