I recently moved and now my computer will not start. After I plug everything into the CPU, the fan runs and the lights on the front of the CPU flash on and off. The power button goes from green to orange and the CPU does not start. What could be the problem?

After I plug everything into the CPU

Let's make sure we use the correct terminology first. The CPU is the central processing unit - a microchip that mounts on the motherboard, installed inside the computer case. You don't plug anything into CPUs. You plug things into the motherboard connections that are exposed on the back of the case.

So my guess is something came loose inside and you need to pop open the side of the case, and trace back all wires to ensure they are correct fastened.

Thank you for the clarification. I mean, when I plug the power cord into the computer, these symptoms occur. I have checked all connections inside and they are all secure.

Well, it could just be a coincidence and perhaps something just decided to fail during the move. I would start with the PSU. The fans spinning only means the 12V is there, but it is not mean the other voltages are fine. To properly and conclusively test a power supply unit (PSU), it must be tested under various realistic "loads" then analyzed for excessive ripple and other anomalies. This is done by a qualified technician using an oscilloscope or power analyzer - sophisticated (and expensive) electronic test equipment requiring special training to operate, and a basic knowledge of electronics theory to understand the results. Therefore, conclusively testing a power supply is done in properly equipped electronic repair facilities.

Fortunately, there are other options that are almost as good. I keep a FrozenCPU Ultimate PSU Tester in my tool bag when I am "in the field" and don't have a good spare power supply to swap in. While not a certain test, they are better than nothing. The advantage of this model is that it has an LCD readout of the voltage. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within specified ATX Form Factor Standard tolerances. Lesser models use LEDs to indicate the voltage is just within some "range". These are less informative, considerably cheaper, but still useful for detecting PSUs that have already "failed". Newegg has several testers to choose from. All these testers contain a "dummy load" to fool the PSU into thinking it is connected to a motherboard, and therefore allows the PSU to power on, if able, without being attached to a motherboard - great for testing fans, but again, it is not a true load or suitable for conclusive testing.

As mentioned, swapping in a known good supply is a tried and trued method of troubleshooting used for centuries, even by pros. Remove the "suspect" part and replace with a "known good" part and see if the problem goes away.

I do not recommend using a multimeter to test power supplies. To do it properly, that is, under a realistic load, the voltages on all the pins must be measured while the PSU is attached to the motherboard and the computer powered on. This requires poking (with some considerable force) two hard and sharp, highly conductive meter probes into the main power connector, deep in the heart of the computer. One tiny slip can destroy the motherboard, and everything plugged into it. It is not worth the risk considering most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.

And remember, anything that plugs into the wall can kill. Do not open the power supply's case unless you are a qualified electronics technician. There are NO user serviceable parts inside a power supply.

The power supply is new. It was the first thing I thought of when it started acting up.

Just to be clear, you moved and the computer did not work. So you replaced the PSU and that did not fix the problem. Is that right?

What else did you try? Is that a stock Intel or AMD heat sink fan on the CPU?

I take it that this is a Desktop machine, and not a Laptop.

After I plug everything into the CPU (tower), the fan runs and the lights on the front of the CPU flash on and off.

Something could have been jostled loose in the move. The above usually indicates a loose connection or a component not fully seated/secured. It could be a cable, or a "card" in a motherboard slot.

(With the tower and anything else unplugged from the wall power outlet) start with the power supply connections to the motherboard, and any components/devices.

Check any cards are fully seated in their slots, and all cables are secure at every connection.



The power button goes from green to orange and the CPU does not start.

As above.