avrdude: verification error; content mismatch

I keep getting this error

avrdude: verification error, first mismatch at byte 0x0000
0x0c != 0x62
avrdude: verification error; content mismatch

I apologize if this has already been covered before. i have found a couple references to it n the forums but i have very little programming experience and what i have run across is way over my head

uploading some basic sketches to this board for the last week and never had an issue. today I plugged in a 9v 1 amp wall wart and since then it has note been able to upload anything. Did I damage my board? can anyone explain this issue to a total nubbie?

Your help is greatly appreciated. I’m trying to use the board to make a little pumpkin light show with some RGB LEDs. I don’t want to disappoint the family on this, but i would hate to have to go buy a new board.

Also my L led on the 13 pin, keeps flashing 3 quick, 1 long off.

I get the same error if i try to upload any sketch even blink.

hitting the reset button doesn't seem to do anything for me.