Holding the 3 buttons to enter the re-writting mode, does light up the LED light ?
If it does, press refresh button and see if the serial number comes up underneath
If it doesn't, then try a hard reset.
Unscrew the palm rest and using a paperclip or a wire, put each end on each boot plate, whilst plugging in the usb in the PC. That should hard reset the keypad
and LED light should come on.
Then proceed with the reflashing video guide.