Hi ,i had same problem several times during repair-this is logic board fail-nothing u can do about but notrh bridge may not work correctly or connector is bad(missing pins)...without microskop, repairing ,resoldering,reboling ))logic board.... u can try get rid of DVD ROM and install hard drive internally as a second HD(sure with no first one)...that mean u will boot up from it,and will download some files and etc.Or use your Mac as minimac,imac but not laptop anymore.This is temporary solution b/c this hard drive would be not a primary...You are dealing with broken logic board,period.