Hi,
I have been using my Arduino for a few weeks now without issue. Yesterday, I set pin 3 to pinMode INPUT and accidentally connected 12V (I had 2 wires, 3.3 and 12, lying right next to one another). I saw a huge puff of smoke, and suddenly the port button under the tools tab in IDE was greyed out. I assume that I broke this board. Luckily, I had a backup! I was using the back-up for a few hours when suddenly, the board stopped working, and the port button was greyed out again. I have since plugged in a friend's Arduino to my computer, and it works fine. Is there something I can do to fix the second (or even the first) board? I have tried uninstalling IDE, resetting the computer, uninstalling various drivers, double-pressing the reset button, and pretty much anything else I have found online. What might I have done to break the second board? Thank you for any help you might give me - I am a bit of a newbie to Arduino.