That is a fried voltage regulator.
Stop trying to use your board before you burn more things downstream.
You can try replacing it
http://www.ebay.com/itm/10X-AMS1117-5-0-5V-LDO-SOT-223-Voltage-Regulator-10Pcs-SHIP-TODAY-New-/181985964500?hash=item2a5f3571d4:g:CjcAAOSw3ydV7WIR
if you know how to solder, and haven't fried anything else on the board.
You COULD keep using the board if you have a trusted, regulated, 5V power source. You can plug that into the 5V pin and GND.