Again, check all the connections a half a millimeter sticking out is enough to distort the connections, and the XO etc. buttons and power board and the mobo (in other words the ABXY buttons serves as a bridge between the powerboard (the small part with the switch for turning on/off and hold) and the mother board. Even if the socket for the AC adapter is connected if the switch isn't connected right it won't turn on, so check the connections.