Problem with connecting Arduino Uno to PC through USB

Using Arduino IDE 1.x
1

Hi,

I have an Arduino Uno R3 and I was working on a project that involves using a pot and a 9V battery and it was working well, but then after I was done with the project, and wanted to connect the Arduino to the PC through the USB cable, the PC couldn't read it as it didn't appear anyway in Device manager or in tools tab.

What is weird to me that the board is working well because of the following:

  1. The "L" and "On" LEDs are on even when it is powered through the USB cable
  2. the Last sketch I uploaded is working well and as expected.
  3. All PINs are working
  4. I used another Arduino board as ISP to upload a new sketch to the broken board and it worked.
    5)I tested the USB cable with the other Arduino to upload a new sketch and it is working with no problem

Important notes:
I tried uploading a new clean sketch, reset, burn bootloader but nothing fixed the issue
The TX and RX light didn't work when I tried all of that.

My question:
What are the possible reasons for this issue and how to fix it?

Thank you

2

was working on a project that involves using a pot and a 9V battery

Please share the schematic and code used for this project

3

Not clear to me what you have done but ....If using the second Arduino you “ uploaded using programmer” to the “ broken” board then you have overwritten the bootloader and you will need to re load that before you can communicate over the usb connection