If when you boot your Windows 11/10 device and the computer fails to boot successfully and throws any of the BIOS Power-On Self-Test (POST) error codes, then this post is intended to help you with the solution you can try to resolve the issue.
Fix BIOS Power-On Self-Test (POST) errors
When you encounter a BIOS POST error code (head over to Oracle.com for a list of POST codes and their descriptions), it’s usually accompanied by a single or more computer beep sound.
If you encounter any POST code error, you can try our recommended solutions below in no particular order and see if that helps to resolve the issue.
- Remove new hardware
- Unplug any disks or USB devices
- Disconnect external devices
- Reconnect and check power cords
- Identify beep code
- Check fans
- Check cables
- Disconnect all expansion cards
- Disconnect all drives
- Remove RAM
- Power cycle the computer
- Disconnect and reconnect the CPU
- Check if BIOS chip is loose
- Clear CMOS
- Update BIOS
- Replace motherboard, CPU, RAM, PSU
Let’s take a look at the description of the process involved concerning each of the listed solutions.
Note: To carry out most of thes instructions, you may require the services of a hardware technician.
1] Remove new hardware
If you recently added new hardware to the computer, remove that hardware to make sure it is not the culprit. If your computer works fine after removing the new hardware, then it’s either the new hardware is not compatible with your computer, a system setting needs to be changed, or the new hardware is defective.
2] Unplug any disks or USB devices
Remove all disks, CD/DVD that are in the computer. If any USB devices (iPods, drives, phones, etc.) are connected, disconnect all of them as well. Reboot the computer and see if anything changes.
3] Disconnect external devices
Disconnect all devices from the back of the desktop computer, except the power cable. Turn on the computer and see if it beeps normally. If the computer has never beeped, keep the monitor or display connected to see if any change occurs.
4] Reconnect and check power cords
If the computer is not getting enough power or the power is getting interrupted, you may encounter any of the BIOS POST error codes. Disconnect your power cables from any power strip or UPS (uninterruptible power supply) and connect the computer directly to a known good wall outlet and see if that helps.
5] Identify beep code
If you are receiving a sequence of beeps, see a listing of different beep codes and their explanation. You can also check your motherboard or computer documentation for information on the beep codes. These beep codes are meant to help identify which computer component is failing or bad. If your beep code is not listed, continue troubleshooting.
6] Check fans
Make sure all fans are running on the computer. If a fan has failed (especially the heat sink fan for the CPU), your computer could be overheating or detecting the fan failure, causing the computer not to boot and consequently trigger a POST code error.
7] Check cables
Verify all the cables are securely connected to the computer and that there are no loose cables by firmly pressing in each cable. Ensure all disk drives should have a data cable and power cable connected to them. Also, your power supply should have at least one cable going to the motherboard. Many MOBOs may also have additional cables connected to them to supply power to the fans.
8] Disconnect all expansion cards
If the above recommendations still have not resolved the irregular POST, disconnect the riser board (if applicable) and each of the expansion cards. If this fixes the problem or allows the computer to POST, connect one card at a time until you determine which card is causing the problem.
9] Disconnect all drives
If you cannot diagnose the problem by the beep code (or you do not hear a beep code), power off the computer. Then, disconnect any IDE, SATA, SCSI, or other data cables from the MOBO. After disconnecting them, try booting the computer again.
If this resolves your irregular POST or generates error messages, reconnect each device until you determine which device or cable is causing the issue.
10] Remove RAM
If you continue to experience the same problem with all the above hardware removed, remove the RAM from the motherboard and turn on the computer. If the computer has a different beep code or was not beeping but is now, turn off your computer and try the suggestions below. Make sure to turn off the computer before adding and removing the memory and then turning it back on to see if the suggestion resolves the issue.
- Re-insert the memory into the same slot.
- If you have more than one stick of memory, remove all but one stick of memory and try rotating through each stick.
- Try one stick of memory in each slot.
If you can get the computer to boot with one or more of the sticks of memory installed, you are likely dealing with some bad memory. Try to identify which stick of memory is bad and replace it.
If you can get the memory to work in one slot but not another slot, the motherboard is likely defective. You can either workaround the issue by running the memory in a different slot that does work or replace the motherboard.
11] Power cycle the computer
In some situations, a computer may have power related issues often caused by either the power supply or the motherboard. To help determine if this is the issue, try turning the computer on, off, and back on as fast as possible, making sure the computer power light goes on and off. In some situations, you may get the computer to boot.
12] Disconnect and reconnect the CPU
You can reseat the CPU by removing it and re-inserting it into the socket. You should also apply a fresh layer of thermal compound between the CPU and the heat sink.
13] Check if BIOS chip is loose
If your motherboard has a BIOS chip, it can become loose over time due to heat expansion and cause the computer to give an irregular POST. Gently press down on the BIOS chip to make sure it has not become loose.
14] Clear CMOS
To clear the CMOS, do the following:
- Turn off all peripheral devices connected to the computer.
- Disconnect the power cord from the AC power source.
- Remove the computer cover.
- Find the battery on the board. The battery may be in a horizontal or vertical battery holder, or connected to an onboard header with a wire.
If the battery is in a holder, note the orientation of the + and – on the battery. With a medium flat-blade screwdriver, gently pry the battery free from its connector.
If the battery is connected to an onboard header with a wire, disconnect the wire from the onboard header.
- Wait one hour, then reconnect the battery.
- Put the computer cover back on.
- Plug the computer and all devices back in.
Boot the computer and see if POST error occurs.
15] Reset BIOS to default settings
You can reset the BIOS setting to its default valuesand see if issue is resolved.
16] Update BIOS
Updating the BIOS and firmware on your system could help fix the issue. Since you’re unable to boot to the desktop, you can update BIOS by creating a bootable USB on a working machine and then boot the faulty PC with the bootable media.
Once you complete the manual update of the BIOS/firmware on your system, see if the issue is resolved.
17] Replace motherboard, CPU, RAM, PSU
At this point, if nothing has worked so far, it’s likely you have a case of bad motherboard, power supply, CPU, or RAM stick. In which case, you need to either replace these components or have the computer serviced. You can replace or swap in parts from another computer that is known to work. Do the replacing in this sequence; the motherboard first, then the RAM, the CPU, and finally, the PSU.
Hope you find the troubleshooting outlined in this post helpful!
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