CompTIA A+ 220-802

Answer: B - If the fans spin but there is no power to other devices in the system (most notably the motherboard and CPU) the issue is likely the ATX power connector is loose.

Key Takeaway: The ATX power connector, which is now one large connector that used to be divided into two connector (P8/P9 or P1/P2), needs to be connected to the motherboard for the CPU to function, and therefore for the system to work. You may notice that the fans (which connect directly to the power supply) and perhaps the hard drives are functioning correctly-this is because the connection to those devices is strong. This also demonstrates that power is travelling to the power supply correctly, although it does not rule out a possible problem with the power supply or the motherboard if reseating the connection does not fix the problem.