No device found on COM16

I use the "ReadAnalogVoltage"sketch. Here is the sketch:

void setup() {
  Serial.begin(9600);
}

void loop() {
   int sensorValue = analogRead(A0);
   float voltage = sensorValue * (3.3 / 1023.0);
   Serial.println(voltage,5);
   delay(1000);
}

I connectted "GND" and "A0" for my input which is 2.5V.
And then I tried to upload the sketch and it was showed "No device found on COM16."
I wounder if my arduino due was burned when I touched the board which was very hot.
Thanks.

Few things you can try:

Tools -> Serial Port -> COM16;

If Serial Port is greyed out, disconnect the USB from the computer and plug it back in, that usually works for me.

EDIT: I didn't read the part about it being very hot. That's not normal, do you have another Arduino you can try?

_Oxid: Few things you can try:

Tools -> Serial Port -> COM16;

If Serial Port is greyed out, disconnect the USB from the computer and plug it back in, that usually works for me.

EDIT: I didn't read the part about it being very hot. That's not normal, do you have another Arduino you can try?

I don't have another board and I tried plug it back several times, but it didn't work. Before I connected my input voltage, I tested the "LED blinking" that worked. However, after I tested my circuit, anything didn't work.