At a guess from what you have said the 360 is bricked, you'd have to flash your nand backup back to the 360 with a hardware flasher such as the Nand-X to recover the console.
At a guess from what you have said the 360 is bricked, you'd have to flash your nand backup back to the 360 with a hardware flasher such as the Nand-X to recover the console.