Arduino mega 2560 won't get detected by pc

[abc53]

 I was using the vin pin to power up the Arduino mega. About 10.3 V was being applied and it is working with the code that I uploaded. But I have to make a few changes to the code so I have to connect the Arduino to the pc but it won't get detected. No sound on connecting and no pop up in the device manager also but the board works perfectly fine on the uploadee code. Can anyone help?

[pert]

What do you mean by "the board works perfectly fine on the uploadee code". Are you saying that you can successfully upload to the Mega after connecting it to your PC?

[abc53]

What do you mean by "the board works perfectly fine on the uploadee code". Are you saying that you can successfully upload to the Mega after connecting it to your PC?

No the board works with the previously uploaded code. I am unable to upload any code but the one I uploaded 5-6 days ago , the Arduino just runs that code.

[pert]

I understand now.

Do you see a new port in the Arduino IDE's Tools > Port menu after you plug in the Mega?

If not, make sure you have the USB cable fully inserted into the Mega and the PC.

You may have a damaged/defective or charge-only USB cable. Try a different one.

USB 3 ports can sometimes cause problems. Try a USB 2.0 port or a USB 2.0 hub connected to a USB 3 port.

[abc53]

I understand now.

Do you see a new port in the Arduino IDE's Tools > Port menu after you plug in the Mega?

If not, make sure you have the USB cable fully inserted into the Mega and the PC.

You may have a damaged/defective or charge-only USB cable. Try a different one.

USB 3 ports can sometimes cause problems. Try a USB 2.0 port or a USB 2.0 hub connected to a USB 3 port.

I got the board changed. Though I am still curious why this happened?
Is 10.3 V too much at the Vin of the Arduino board?? Or I had another issue with my PCB. Actually the common area of the PCB is being shorted with the 5V of Arduino maybe because of some bad solder joint ( I have desoldered and soldered all components back but haven't been able to find the cause). But since all the other components are isolated and have their own supply , I ignored this issue and the circuit was working as desired.
Can this be the cause ?

[pert]

Are you saying that you tried a different board with the same USB cable and same USB port on the same PC and the problem did not occur with that board?

[abc53]

Are you saying that you tried a different board with the same USB cable and same USB port on the same PC and the problem did not occur with that board?

Yup.