Power not working

Hi there, tried reflashing my box several times. My problem is that I have a blue light and black screen when using the normal power port. If I power the usb port then this gives a display onscreen? anyone had this issue? if so please provide a solution? not too sure if opening up will let me see if the board is fried. Temp solution just use usb power but no good as unable to use as memory slot.

Thanks in advance for direction.