How to Remove the CMOS Battery to Fix Boot Issues & Reset BIOS

PDF download Download Article
Easily access, remove, or replace the CMOS battery in any PC
PDF download Download Article

If you're having issues with your computer's startup or need to reset the BIOS, you may be instructed to remove the CMOS battery. The CMOS battery helps your computer remember the date and time and its BIOS/UEFI settings, and removing it can sometimes fix boot issues. In this article, we'll go over how to remove the CMOS battery, what it does, and whether you need to replace it.

Quick Steps

  1. Turn off your computer and unplug everything from it.
  2. Lay the computer on its side.
  3. Remove the computer tower's side panel.
  4. Press the lever next to the CMOS battery to remove it.
  5. Gently press the CMOS battery back in place when it's time to replace it.
Section 1 of 3:

How to Remove the CMOS Battery

PDF download Download Article
  1. The materials you may need are as follows:
    • An anti-static wristband . Even if you're working on a non-carpeted floor, an anti-static wristband is still a good idea to avoid creating static electricity that could short out your computer.
    • A new CMOS battery if you're replacing it.
    • A flathead screwdriver to pry the CMOS battery out of your motherboard.
    • A flashlight, especially if you're not in a well-lit area.
  2. Make sure you have a stable table or desk to work on. Avoid working in a carpeted area to cut down on static electricity.
    Advertisement
  3. This includes the power cable, any monitors, and any other peripherals.
  4. This will allow you to see inside the case better.
  5. How you open your PC case may vary slightly depending on your case model, but in general, you remove the thumbscrews on one of the side panels and slide the panel off of the case.
    • The side panel you want to remove is most likely the right panel. However, if your computer is set up differently, you'll want to remove whatever panel will get you access to the inside of the case.
  6. The CMOS battery is a circular battery, also known as a coin battery or button battery. It will be located in a different spot, depending on your motherboard, but it's usually near the bottom of the board.
  7. Many motherboards have a small metal lever next to the CMOS battery that can be pressed to pop the battery out of the motherboard. However, if yours doesn't have that or it's not working, you can very gently use a flathead screwdriver to pry the battery out of the motherboard.
    • If you're trying to reset the BIOS, wait a few minutes before reinserting the battery.
  8. Whether you are placing the old CMOS battery back in the case or a new one, all you need to do to replace it is to set the battery over the battery slot and then press it into place. You may feel the battery click into place. Don't press too hard to avoid damaging the board. [1]
    9. Advertisement
Section 2 of 3:

What the CMOS Battery Does

PDF download Download Article
  1. Most notably, the CMOS battery allows your computer to remember the date and time even when it's turned off. It also stores your BIOS/UEFI settings and helps your computer maintain a low-power state when it is asleep or hibernating. [2]
  2. If your computer is having startup issues, removing the CMOS battery is usually one of the suggested solutions. This is because it will reset your BIOS/UEFI settings to default, which can help if something in those settings is causing your computer to have issues.
    3. Advertisement
Section 3 of 3:

Do CMOS batteries need to be replaced?

PDF download Download Article
  1. However, you may never experience this due to how long a CMOS battery can last. The exact lifespan of a CMOS battery depends on its build quality and how much the computer is used, but it typically can last anywhere from 2 to 10 years, according to HP. [3]
  2. You might notice one of the following when it's time to replace the CMOS battery:
    • An incorrect date and time on your computer
    • BIOS settings are reset
    • Slow startup
    • Boot issues
    • Errors such as "Please enter setup to recover settings" or "System battery failure"
  3. CR2032 batteries can be purchased either online, at a computer store, at a special battery store, or a big box retailer like Walmart or Target. The cost of a CR2032 battery will vary but shouldn't cost more than $10.
    4. Advertisement

Expert Q&A

Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Video

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Submit
      Thanks for submitting a tip for review!

      You Might Also Like

      How to
      Check Browsing History on a WiFi Router
      How to
      Remove Write Protection from a USB Pen Drive
      3 Easy Ways to Find the Publication Date of a Website
      How to
      Connect PC to TV with HDMI
      How to
      Add the Google Play Store to an Amazon Fire Tablet
      Easy Ways to Read Crash Dump Files & Troubleshoot Crashes
      How to
      Bypass Your Screen Time Passcode: Reset, Remove, or Hack Screen Time
      6 Ways to Pair Your JBL Earbuds: Guide & Troubleshooting Tips
      How to
      Turn on Backlit Keyboard on Lenovo
      10 Genius Ways to Cheat a Step Counter on a Phone (No Walking Required)
      How to
      Format a Write–Protected Pen Drive
      How to
      Create Desktop Shortcuts for Files & Websites
      How to
      Guess a Password
      How to
      Restart Your Computer Using the Keyboard
      Advertisement

      References

      1. ↑ https://support.redbirdflight.com/how-to-change-the-cmos-battery
      2. ↑ https://www.hp.com/us-en/shop/tech-takes/what-is-cmos-battery-how-to-remove-and-replace
      3. ↑ https://www.hp.com/us-en/shop/tech-takes/what-is-cmos-battery-how-to-remove-and-replace

      About This Article

      Thanks to all authors for creating a page that has been read 266 times.
      If you buy through links on our site, we may earn a commission .

      Is this article up to date?

      Advertisement