I gave 12v supply to the 5v pin which made the arduino uno R3 to shut down. When I load it again it operated normally(only the Green and orange lights works) by when i tried to upload my program in the arduino it gave me a error message "avrdude: verification error, first mismatch at byte 0x000c0x0c != 0x0e
avrdude: verification error; content mismatch"
The previous sketch does not work after that.
Please help me to fix it.