The detail description is:
1,push the "power" button to let the N770 start to boot
2,N770 show the "NOKIA" in screen then it stopped, dont show the "hand shake" screen.
3,wait several minutes, it automatically power off(At least screen goto off).
try to use Flasher-3.0 to flash the official image(2006 or 2007HE), flash succeeded, but still have same result.