"How to fix keyboard that is not working during startup?"에 답변Zap the PRAM yet? Leave it unplugged a good while, perhaps overnight. If you can get to the battery on the motherboard and CAREFULLY REMOVE IT while it is unplugged that should speed things up as well. It’s working properly do not be alarmed when all of the fans come on full blast. That is your sign that it is indeed rebuilding those settings And will hopefully be back up soon.