Problem uploading code to my UNO,can't find port anymore

Using Arduino Avrdude, stk500, Bootloader issues
1

Hello Community,

I have been suffering from this problem from past 3 days.
It started from showing me this error:

avrdude: ser_open(): can't open device "\.\COM15": The system cannot find the file specified.

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
Error downloading http://arduino.esp8266.com/stable/package_esp8266com_index.json

I couldn't fix this and I came up with a new problem that my COM ports are also messing with me, they're not chosen correctly and even after choosing right port it shows no right port is chosen .
and now its that i can't even see my ports,the port option has been greyed out even when my UNO is connected .I don't know what to do now.
Please help me with this problem,any advices or suggestions are welcome and would be appreciated.

Thanks.

2
  1. Disconnect everything from the board (shields...). Shields which use Rx,Tx pins can block communication via USB. On-board USB/serial transceiver uses same pins.
  2. Connect the board to the PC. Check the device manager if the board is visible.
  3. If yes then COM port should appear in the IDE.