The Due is a 3.3V device, the Mega a 5V device; I hope you did not damage your Due.
If the Mega is still recognised by the PC, you first can try the loopback test. If that works, get an Uno and burn the bootloader.
The Due is a 3.3V device, the Mega a 5V device; I hope you did not damage your Due.
If the Mega is still recognised by the PC, you first can try the loopback test. If that works, get an Uno and burn the bootloader.