Black screen on my HP Notebook-15-f125wm Touch

Black screen, cap lock, power, wi-fi, hdd led’s were blinking once. Followed HP procedure with removing battery holding power button for a minute. removed battery, connected to charger only no activity. Changed mem stick as request from HP automated help, lights stopped blinking fan turns on 5 sec’s shuts off. Tried external display nothing, unhooked internal display cables, reconnected external display same result. Replaced MB as recommended by Support staff, same result. Purchased a new power switch and the specs it was made with were off and would not seat in slot ( card material 3 times thicker than original, button bigger ) returned it. Mem stick, hdd and wi-fi card all work in different system. Could the power switch have gone bad? At a total loss here.