Arduino mega R3 Atmega2560-16AU CH340 can't detect on my computer

I made a search on google before this threads, as my problem is not solved yet. this is not my first arduino project but it is my first time to use ARDUINO MEGA R3 Atmega2560-16AU CH340G Board. the problem is: my computer(Windows 10) can't read the board (Arduino mega R3 Atmega2560-16AU CH340G) thats why Arduino IDE can't detect the port of the board and i can't upload a code to my board because of that.

i open the device manager of my laptop but still it is not on the port and in the other devices when i connect my board. also it has no sound when i connect the board in to my laptop. i also try to replace the USB cable and insert to another port of my laptop but still it didn't read the board. i also try to install the driver of ch340. http://www.wch.cn/download/ch341ser_zip.html (this is the link where i download the driver of ch340) still didnt read the board i try to test my Arduino UNO and it is working on the USB cable and port of my laptop that's why i conclude that the problem is not in my usb cable and port of my laptop.

the R18 LED is ON or HIGH (RED) and the R17 LED is blinking (RED) in my board when i powering it up or connecting to my laptop.

please help/any suggestion to fix this. thank you.

(deleted)

Remove anything connected to the board.

Can you see COM and LPT ports in device manager ? If not you may need to enable "SHOW HIDDEN DEVICES" to see them.

Does your board make the HARDWARE CONNECTED sound when connected or disconnected ? If not then you may have broken it.

If you get the HARDWARE CONNECTED sound but no COM port then you may need the driver. Available here

Bob.

It doesn’t have HARDWARE CONNECTED sound when connected or disconnected.

theres is not hardware connected sound and no COM port even in the device manager even if i enable show hidden files the arduino mega is not in he LPT ports or other devices in device manager.

MOD EDIT

You have a UNO showing on COM 3

That is NOT a MEGA !

From the IDE select the UNO on COM 3 to try an upload.

Bob.

i’m using UNO with my last project that’s why UNO is in the lpt ports and if you see the name Arduino UNO (COM3) it is color gray it means it is the history of the port you have been connected.

Windows tends not to show past devices unless viewed using and extended option.
Given that you had a UNO and the MEGA does not react with windows in any way it would appear the device is dead.
How it died only you would know that.
Most often it is shorting the power bus somehow.

Bob.