Technology in terms you understand. Sign up for the Confident Computing newsletter for weekly solutions to make your life easier. Click here and get The Ask Leo! Guide to Staying Safe on the Internet — FREE Edition as my thank you for subscribing!

Is there a way to test a machine that won't boot to see if the BIOS is the problem?


My computer went dead. I’ve tried everything, but have come to the conclusion
that the problem is either a bad CPU or a damaged BIOS. How can I test the BIOS
to see if I’m right on a computer that won’t boot and if the BIOS is bad, can
it be flashed?

In this excerpt from
Answercast #80
, I look at a machine that won’t boot and the likelihood that
it is a BIOS problem.


Test for a BIOS problem

Well… I will admit that, to me, it is extremely unlikely that it’s the BIOS.

BIOS is just some software. Now granted, it can become corrupt – but if it does, and if the computer won’t boot, or can’t even come up to a BIOS configuration screen, then I honestly don’t know of a way to fix that.

Hardware failure

It’s more likely to be some kind of hardware related issue.

Now, I’m not sure what steps you’ve taken that lead you to believe that it’s either the CPU or the BIOS. However, there are so many things on the motherboard, for example, that could cause the thing to appear completely dead – that it could, in my mind, be just about anything. It could be anything hardware related on that computer.

Ultimately, I really think that the only true solution to a problem that’s this severe is to take the machine to a technician. See if they can diagnose, specifically, what it is that’s wrong. Then you can make a decision as to what the correct steps are to repair, or potentially replace, the machine.

(Transcript lightly edited for readability.)

Do this

Subscribe to Confident Computing! Less frustration and more confidence, solutions, answers, and tips in your inbox every week.

I'll see you there!

7 comments on “Is there a way to test a machine that won't boot to see if the BIOS is the problem?”

  1. I had that happen to me once. What I did , out of desperation, was remove the battery from the mother board for twenty or so minutes, then replace it. This resets the Bios to its defaults and may allow you to reboot your machine. If it works, then you have a cheap fix, if it doesn’t, then off to the tech or buy a new motherboard.

  2. Sorry to have missed this. You can also buy a new battery for the motherboard instead of putting the old one back in ( the old one may just be dead ).

  3. Some trouble shooting procedures you can try for for desktops.
    (1) Enure monitor works by testing on another computer or disconnect data cable and check if colored logo appears.If working reconnect data cable

    (2) Disconnect most connections except power supply to motherboard. This includes the hard drives & DVD, all peripheral connections such as usb and internet,mouse & keyboard.

    (3) Switch computer on. Does the power supply fan start start ..does the CPU fan start ? Test with small taper of paper if not sure.
    If no power. replace power supply.

    (4) BIOS self checking text {P.O.S.T} should appear on the screen advising various peripherals cannot be found . If this happens reconnect one peripheral at a time and restart after each connection. The idea is to isolate the failed component.
    (5) If P.O.S.T fails but power supply appears to be working, take out ram, and replace one stick of ram at a time. Initially try a different slot if possible. Do NOT touch contacts with hand or cloth material if possible {static electricity}


  4. It is highly unlikely that your BIOS would cause your computer not to boot, but it is possible. The actual physical chip that contains the BIOS software can go bad for various reasons (voltage, heat, corrosion, bad solder joints, etc.).

    (Assuming you are not under warranty)
    For a computer that will not turn on (no lights, no sound), I would first look to the power supply.

    If the power supply tested fine (you need to use a voltmeter – those plug in power testers are not accurate), then test out the RAM by removing one module at a time or trying a known good RAM stick.

    The only thing you should have connected at this point is your power supply, at least one stick of good RAM, and your motherboard.

    If that still does not work, then check your power switch. I’ve seen it on 2 occassions where the power switch became disconnected from one of the wires. To test your power switch, you can use a small metal object to touch the 2 pins connected to your motherboard that completes a circuit that causes your computer to turn on.

    If all of the above fails, then you are likely looking at a bad motherboard. Repairing it is usually not an option for the normal person without very specialized, and expensive, equipment with the knowledge to use it. It’s usually best to just replace it at that point. If it’s an expensive motherboard, you can try one of the online businesses that offer the service. Or you may get lucky and find someone local.

  5. “I’ve tried everything” – depends how dead is dead. As long as the computer would run a CD, things could still be done:


Leave a reply:

Before commenting please:

  • Read the article.
  • Comment on the article.
  • No personal information.
  • No spam.

Comments violating those rules will be removed. Comments that don't add value will be removed, including off-topic or content-free comments, or comments that look even a little bit like spam. All comments containing links and certain keywords will be moderated before publication.

I want comments to be valuable for everyone, including those who come later and take the time to read.