Can't Activate Serial Monitor ("COM10 is busy")

I know this maybie is a common issue, but i can’t find a solution fastly enough every time it happends to me, please move this post to wherever must be assuming this is not the place:

I have the 1.6.5 arduino IDE in windows 10 (migrated from 7), i’m using one Arduino UNO

Ok, i was working on some code to try to automatize things with temperature-based inputs, i’ts not finished but i was trying to get some information through the serial monitor, it was working just fine but then, something happend (i close the Serial Monitor) and now i can’t open it back.

The code:

#include <Servo.h>

Servo myServo;

const int sensorPin = 0; //entrada del sensor

long miliVolts;
long temperatura;

long chico=100;
long grande=1;

void setup() {
  Serial.begin(9600); // inicia comunicación serial

void loop() {
  miliVolts = (analogRead(sensorPin) * 5000L)/1023; // Calculando los mv de la entrada
  temperatura = miliVolts/10;

  int regulador = map(temperatura,10,40,0,255);

  if (chico>temperatura)
  if (grande<temperatura)

  Serial.print("Temperatura: ");
  Serial.println(" grados");
  Serial.print("la menor temperatura registrada es: ");
  Serial.print("la mayor temperatura registrada es: ");

It’s not the first time it happend to me, i try to change the port of the arduino and still doesn’t open

Any suggestions, ideas, questions?

All would be apreciated if helps to solve the problem

Is there a dead serial monitor or other program that might be clinging to the port?

Failing that, try these:

disconnect the arduino and reconnect it

restart IDE

reboot the computer

It is possible to get the system confused such that a program that's no longer running didn't properly let go of the serial port, and is still clinging to it from beyond the grave - the message "COMx is busy" means that the computer thinks some other program is already using it.

I have the 1.6.5 arduino IDE in windows 10 (migrated from 7), i'm using one Arduino UNO

Uploaded windows 10 last night and have been struggling since. Check your USB connections to the arduino to make sure they are good. Go to device manager and look at Ports and see if a com port is listed. If you don'r see ports in device manager, go to view and check show hidden devices. If the comport you have been using is listed, you can open properties > port settings > advanced and use the comport drop down to assign the current com port you are using to the old com port number. Usb comports often get orphaned and another comport number is assigned when the arduino is plugged in.