hello evry one
i've got a weird issue 
i have an arduino uno R3 and it was working fine.
now my computer doesn't detect it (i can't find even the com port or non identified devices in the device manager)
that was when i was trying a GSM shieled with 9V 2Amp power like the datasheet says
the weird thing that when i plug my arduino to the USB 3.0, the light "ON" on the board turn on, but when i plug it to USB 2.0, nothing happen.
what i did:
i remove evry other connection from the arduino
i tried with another cable
i tried other devises on my USB 2 and 3, they works fine
i tried to use my arduino on another computer, same problem
(i dont have another arduino to know what's making this problem)
i tried to reset (with button and with jumper) -> the led L does not blink
what i think the problem is:
probably the problem is in the arduino not the computer
maybe when i plugged the power 9V 2Amp and plug to the computer in the same time (and i dnt think it can be a problem)
maybe there is a problem with the bootloader
please help me, at least how can i know what it the problem, did i harm something or evrything
To what did you connect the 9V? Barrel jack? Vin? 5V? On the Arduino or the shield?
It should be possible to have power connected from the computer and the 9V at the same time.
Sounds like you have blown something 
With my knowledge of how it all works:
-
The 328 should flash the pin13 LED at power up. If that does not happen, I think that that is an indication that the 328 is permanently damaged. If the 328 micro is the DIL version (longs and narrow) and not the SMD version (small, square), you can replace it and hope that that was the only thing you blew up.
2)
Because there is no communication, you also damaged the USB micro.
thnx fo replaying
i connect the 9V to the barrel jack and i dont think that i did something wrong
the pin13 Led doesn't flash bearly you can see the light
i have the DIL version. i will buy another one and i wish it's the only thing that was damaged
i will try to install the bootloader to the older one and if it works i will post that
and any suggestion, about is there any thing i can do to protect my arduino when testing the "GSM module sim900 icomsat 1.1", because i didnt even establish a serial communication, and the result damaging my lovely arduino
i bought a new Atmega328P, the new thing that when i connect my arduino to the computer, the led13 L flash then stay on, and the reset button seems working
but the computer like before, it doesnt reconise the arduino as COM port or as non idendified device.
i tried that with another computer, same problem
Can you supply a picture (your own picture) of the board.
It maybe that you just need drivers such as the CH340 ones (or 341)
it was working fine, and like i sayd, it suddenly stopped working when i was testing a gsm shieled
There are a few problems mentioned around the forum about GSM shields.
I would suggest you look to those first by using the search box right at the top of the page and maybe pick out some of the more recent ones.
There are a variety of GSM shields so it could be that it uses pins the Arduino needs whilst programming.
if it works without the shield then you can at least isolate it to the shield completely as the issue.
Was there any documentation with your GSM shield ?
hassen_tayech:
i bought a new Atmega328P, the new thing that when i connect my arduino to the computer, the led13 L flash then stay on, and the reset button seems working
but the computer like before, it doesnt reconise the arduino as COM port or as non idendified device.
i tried that with another computer, same problem
Did you buy one with a bootloader? Else it will never work as before. You can find information to burn the bootloader itself into the 328 chip; I'm not sure what is required.
