How to Fix Problems that Occur During the POST
Table of Contents
Sometimes your computer may actually turn on, but an error message during the Power On Self Test (POST) will stop the boot process. Other times, your PC may simply freeze during the POST with no error at all. Maybe all you see is your computer maker’s logo.
There are a number of BIOS error messages that can display on your monitor and several reasons why a PC might freeze during the POST, so it’s important to step through a logical process like the one I’ve created below.
Time Required: Anywhere from minutes to hours, depending on why the computer stopped booting during the POST
How to Fix Stopping, Freezing, and Reboot Issues During the POST
Walk through these steps in order to address the most likely and easier-to-solve tips first.
Troubleshoot the cause of the BIOS error message you see on the monitor. These errors during the POST are usually very specific, so if you’ve been fortunate enough to receive one, your best course of action is to troubleshoot to the specific error you see.
If you don’t fix the problem by working through the specific error during the POST, you can always return here and continue with the troubleshooting below.
Disconnect any USB storage devices and remove any discs in any optical drives. If your computer is trying to boot from a location that doesn’t actually have bootable data on it, your computer could freeze somewhere during the POST.
If this works, be sure to change the boot order in BIOS, making sure that your preferred boot device, probably the internal hard drive, is listed before USB or other sources.
Clear the CMOS. Clearing the BIOS memory on your motherboard will reset the BIOS settings to their factory default levels. A misconfigured BIOS is a common cause of a computer locking up during the POST.
If clearing the CMOS does fix your problem, make any future settings changes in BIOS one at a time so if the problem returns, you’ll know which change caused your issue.
Test your power supply. Just because your computer initially turns on doesn’t mean that the power supply is working. The PSU is the cause of startup problems more than any other piece of hardware in a computer. It very well could be the cause of your problems during the POST.
Replace your power supply immediately if your tests show a problem with it.
Don’t skip this step thinking that your problem can’t be with the power supply because your computer is receiving power. Power supplies can, and often do, partially work, and one that isn’t fully functional must be replaced.
Reseat everything inside your computer. This will reestablish cables, cards, and other connections.
Try reseating the following and then see if your computer boots past the POST:
Unplug and reattach your keyboard and mouse as well. There’s little chance that either is causing your computer to freeze during the POST, but just to be thorough, reconnect them while reseating other hardware.
Reseat the CPU only if you think it may have come loose or might not have been properly installed.
I separated out this task because the chance of a CPU coming loose is slim, and because reseating one could actually create a problem if you’re not careful. There’s no reason to worry as long as you appreciate how sensitive a CPU and its socket/slot on the motherboard is.
If you’ve built your own PC or made hardware changes, triple check every hardware configuration.
Check every jumper and DIP switch, verify that the CPU, memory, and video card you’re using is compatible with your motherboard, etc. Rebuild your PC from scratch if necessary.
Don’t assume that your motherboard supports certain hardware. Check your motherboard’s manual to verify that the hardware you’ve purchased will work properly.
Check for causes of electrical shorts inside your computer. This could be the cause of the problem if your computer freezes during the POST, especially if it does so without a BIOS error message.
Start your PC with essential hardware only. The purpose here is to remove as much hardware as possible while still maintaining your computer’s ability to power on.
If your computer starts normally with only essential hardware installed, proceed to Step 10. If it still isn’t displaying anything on your monitor, proceed to Step 11.
Starting your PC with its minimum necessary hardware is very easy to do, takes no special tools, and could provide you with valuable information. This isn’t a step to skip if, after all the steps above, your computer is still freezing during the POST.
Reinstall each piece of hardware that you removed earlier, one piece at a time, testing your PC after each installation.
Since your computer powered on with only the essential hardware installed, those parts must be working properly. This means that one of the hardware components you removed is causing your computer to not turn on properly. By installing each device back into your computer and testing each time, you’ll eventually find the hardware that caused your problem.
Replace the non-functioning hardware once you’ve identified it.
Test your computer’s hardware using a Power On Self Test card. If it’s still freezing during the POST with nothing but essential hardware installed, a POST card will help identify which piece of remaining hardware is causing your computer to stop booting.
If you don’t already own or are unwilling to buy a POST card, skip to the next step.
Replace each piece of essential hardware in your PC with an identical or equivalent spare piece of hardware (that you know is working), one component at a time, to determine which piece is causing your computer to stop during the POST. Test after each hardware replacement to determine which component is faulty.
The average computer owner doesn’t have a set of working spare computer parts at home or work. If you don’t either, my advice is to revisit Step 11. A POST card is very inexpensive and is, in general, a smarter approach than stocking spare computer parts.
Finally, if all else fails, you’ll probably need to find professional help from a computer repair service or from your computer manufacturer’s technical support.
If you don’t have a POST card or spare parts to swap in and out, you’re left not knowing which piece of your essential computer hardware is not working. In these cases, you’ll have to rely on the help of individuals or companies that do have these tools and resources.
Tips & More Information
Did I miss a troubleshooting step that helped you (or might help someone else) fix a computer that’s freezing or showing an error during the POST? Let us know, and I’d be happy to include the information here.