Fix A Computer Not Posting

Suppose your motherboard has power, and your computer still won’t post. In that case, it strongly indicates that something is improperly configured or the motherboard or other component is faulty.

Here are some of the symptoms that may be happening to indicate a no-post situation:

  • Q-Codes or Error Codes that indicate a problem: Most modern motherboards have a small segment display with a code that helps you determine the cause of post failures. Check the code with the manual of your specific motherboard.
  • Beeping: You could have a single beep or a series of beeps. Some could be short, and others long. If your motherboard has it, you might have to connect a speaker to the header pin connectors.
  • Power light: You could hear nothing and only see a power light.
  • Cooling fans: Your computer could have the fans spinning and nothing else much happening.

Important: For this troubleshooting guide to be effective, we are going to assume that you have checked your power supply. This can be by testing it on another computer or replacing it with a new one.

The power supply is a crucial component, and we cannot ensure proper testing of any other computer part if the power supply hasn’t been checked first.

Troubleshooting A Computer Not Posting

Go through these steps to help you track down the problem. Removing all non-essential components first will help speed up the diagnosing process and reduce the number of components that could cause problems.

Tip: Get to the problem faster by checking any Q-Codes displayed by your motherboard and comparing them with the motherboard’s manual. This will quickly get you looking at the specific area of concern.

Beeping Sounds: If you hear beeping when trying to start your computer, you can get an idea of which component could be at fault by observing the beep sequence. This will be more likely for older motherboards.

1. Set up your workspace and prepare your computer

  • Find the motherboard manual: If you can download the motherboard manual. If you have kept it, well done!
  • Get a screwdriver: Find a Phillips screwdriver that fits nicely in the computer’s screws.
  • Move to a good work area: Set your system up in a location that’s easy to work on. Lots of free room that is clutter-free around the computer is great.
  • Ground yourself: Before touching any components, touch the case to limit potential electrostatic discharges.
  • Unplug everything: Before following any steps, ensure you have unplugged the power to the computer. Also, disconnect all other plugs or cables connected.

2. Disconnect all drives

A SATA Data cable.
A SATA power connector.
A computer hard drive with the connector area highlighted.

Unplug all the power connectors to all drives. Then, unplug all data cables connected to your motherboard. You can do this at the cable’s drive end to help make reconnecting easier. It will also help you track which cable was connected to which drive.

3. Remove all add-in cards

Unscrew all the cards that are plugged into the motherboard. Remove them all by pulling them evenly straight up and level.

If your motherboard doesn’t have an onboard graphics output, get your hands on a different graphics card and replace your existing one. If you don’t have another one to try, leave it plugged in for now.

4. Disconnect all fans (Except the CPU fan)

The four pin connector of a computer fan for the CPU.

Unplug all the fan connections from power. Some will be connected to the motherboard using pin header connections, and others will be plugged straight into the power supply.

Once they have been unplugged, check that you still have your CPU fan connected. This will be the fan attached to a heatsink that is screwed or clipped directly on your motherboard.

5. Remove the BIOS battery

A wire and plug-style CMOS battery is plugged into a motherboard pin header socket.
A coin cell CMOS battery in a socket on a motherboard.

Gently remove the BIOS battery. This is a silver coin cell battery that keeps the information held in a memory chip. This keeps all the settings for various hardware functions operating as set by the user.

If you cannot see it, look in your motherboard manual to find where it is situated. Sometimes, some cables or drives, etc., can obstruct your view.

Sometimes, I have found batteries that have gone below circuit voltage and unleashed a variety of problems. I have also found some to have high internal resistance, causing more issues.

The computer doesn’t need it installed to run. It will operate fine without it. All it does is retain the settings you have saved in the BIOS when power has been disconnected from the computer altogether.

Important: Make sure that you have no power connected to the computer for about five minutes with the battery removed before continuing.

6. Reconnect a keyboard, monitor, and mains power

Plug your keyboard, the monitor’s display cable, and the main power cable to the computer. Make sure the power is turned on.

7. Press the power button

Press the power button and observe. If the computer starts normally, congratulations! All you have to do is add each component to determine the cause.

If you still can’t get it to start, continue with the guide.

If the computer still won’t post

Now we are getting down to the final few components causing a problem if you have made it this far. Follow these instructions until you reach the stage where your computer posts again.

Disconnect all front panel connectors from your motherboard. You must use a screwdriver, tweezers, pliers, or anything else that can short out the pins instead of the power button from your computer’s case.

The correct power button pins will be shown in the manual. If you can’t get your hands on your motherboard manual, take a photo of the front panel connectors before removing them. The most important pins to memorize are the power button pins.

The remaining suspects:

  • CPU: This is the brain of the computer. It’s the component that processes all the information for your system.
  • RAM: This keeps all the data ready for your CPU to use, amongst other things.
  • Motherboard: This is the main board secured to the case that everything plugs into.
  • Graphics card: It sends all visual data from your computer to be displayed on the monitor.

Eliminate the graphics card

A computer's graphics card with three cooling fans.

If you have already removed your graphics card or are using the display output from the motherboard for the monitor, skip this step.

If you are using the original graphics card from when the computer went faulty, it’s time to swap it out with a replacement to test if it was the cause.

If you are on a tight budget, purchase a cheap card to get you by. In the meantime, there is nothing wrong with that. It can also be kept as a test card for the future if it turns out that it wasn’t the cause of your problems.

Eliminating the RAM (Random Access Memory)

A desktop computer's RAM modules or sticks.

In my computer repair career, I have had a handful of times where I found RAM to be truly faulty. A RAM module is often blamed when it is simply a RAM contact problem.

Please follow my guide on how to clean the RAM contacts properly.

If cleaning the RAM still leaves you with no posting, try leaving one module at a time and cycle through the modules.

If the situation remains unchanged, it’s most likely not the RAM at fault.

Eliminate the CPU and motherboard

A computer's CPU.
CPU
A standard desktop motherboard.
Motherboard

I’m afraid that the only way to test a CPU is by replacing it and seeing if the computer posts. The motherboard can be just as difficult unless you are trained to repair them.

If you have the spare parts, it will be easy to figure out which is faulty by swapping one of them. But for most average people, spare parts aren’t just hanging around.

If you are determined to fix your computer yourself, check the motherboard for signs of damage, burn marks on components or the board, or swollen capacitors.

Bulging capacitors.

If you see anything unusual, replace your motherboard. I have seen more faulty motherboards compared to CPUs, provided that some CPU overclocking was never applied.

Alternative Option: You could take the CPU and motherboard over to your local computer store to ask them to test them for you. They would most likely have spares to test either your CPU or motherboard so you can eliminate the faulty component.

Double-check that the CPU cooler is making proper contact with the CPU. If your CPU gets hot extremely quickly, it can cause the computer not to post.

Please see my article on checking if a CPU cooler is mounted properly to eliminate this.