PORT Option in Arduino Grayed out, can't open device on \\.\COM3

Hello everyone,

So I have been using my arduino for few months now. Everything was fine until one day when I was "playing" with connecting the arduino to Node-Red software. I had to upload the "Firmata" Example from the arduino and I managed to connect it, everything was working fine. Few days after that, I wanted to make a new project with my arduino, and from that day I cannot fix the issue :

" Arduino: 1.8.3 (Windows 7), Board: "Arduino/Genuino Uno"

avrdude: ser_open(): can't open device "\.\COM3": The system cannot find the file specified.

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions. "

Things I have tried:

  • Resetting the Arduino
  • Reconnecting the Arduino
  • Reinstalling the Arduino Software
  • Changing the COM Port
  • Changing the programmer type in arduino software (e.g. ArduinoISP, AVR Isp etc.)

If you need some more information, just ask I'll respond fast.

Thanks in advance :) :S