If u have a Power adapter that is Micro USB, 5v, 2 ~ 3 amps, use it to test if the screen will boot up again or not, while resetting it, there is a micro USB port in the back of the screen.
If it boots up then reattach to the ribbon and see if it’s good, if not ribbon need a change, otherwise it needs a reflash, just follow the guide and u will have it back.