I've been doing my best to avoid posting on forums while learning Arduino, but I could really use some advice now.
After having just successfully driven a 12V fan with a MOSFET for the first time, I tilted the board to see the pin numbers (instead of just leaning forward) and touched the 6 unmarked pins next to the disconnected USB port, which I believe to be the ICSP pins for the 8U2 USB-serial convertor chip, against live exposed solder carrying 12V from a PC PSU. Several or all of the LED's lit up, which alerted me to my stupid mistake.
Now, when I connect the USB, the On and pin 13 LED's turn on, but when I try to upload a sketch the Rx light briefly flashes three times and about 10 seconds later I get the error:
avrdude: stk500_getsync(): not in sync: resp=0x00
My question is: Although I understand it might be possible to reflash the firmware for the 8U2 chip, is it likely that I have fried it completely with 12V and should I just order a new Arduino now?