If your 5V regulator is not burned up, it is damaged. You can see a burn mark on it in your picture. If it is working, it won't be soon. The fact that you have 3.3V selected and it is the 5V reg taking the hit would suggest it is something on the input to the 5V regulator (too high of a voltage) or a short after that. Connected to the 5V line are the LED, C2, C3, and the 3.3V regulator. I doubt the LED would blow it even if it shorted out since R1 would still limit current. C2 may be a crappy cap and shorted internally, or perhaps there is solder shorting out under C3. Finally, the 3.3v regulator may be shorted from Vin to GND. Unless they are using counterfit regulators, I would be surprised if the regulator is defective. I suspect the cap, C2. You could desolder it and see if things work with it removed. It is just a filtering cap and won't break the circuit with it removed (but might make the supply noisey.)