sketch uploads, runs then will not start on reset

This forum is so large now that finding answers is difficult, therefore I ask a question that has probably been asked before.

Blink sketch uploads to UNO through Linux, runs fine (Windows gives me a sync error). I unplug the UNO, (USB) plug in again and LED 13 blinks 4 times in rapid succession, repeatedly. Blink sketch is gone. Tried running off 9v, as I have done before, same thing. Reloaded the sketch several times with same results. I burned the bootloader on this chip yesterday using Adafruit's shield, everything showed ok. Is my board fried? No ATMEGA 328p's work. (tried 4)
Thanks,
Jim

Blink sketch uploads to UNO through Linux, runs fine (Windows gives me a sync error)

Sound to me like Windows knows what it is talking about, for a change.

Is my board fried? No ATMEGA 328p's work. (tried 4)

If the chips all fail the same way, I would not suspect the chips, then. I'd try a different board.

I will try another board, but I am curious as to what I have done to make this happen? My other boards have never done this, and I don't want to go destroying things anymore... although that can be fun, too ]:smiley: