avrdude error while uploading

kprims:
Just a quick check. You do have the ON/Power led on, on both Unos?

Yes now the Led L is on on both UNOs!! I think now it did burn the bootloader :smiley: !!

And yes now y old Arduino is working perfectly !! I uploaded the simple Blink sketch and it works!!! :slight_smile:
Thank you everyone for your great help! :slight_smile: