How To Change Your CMOS Battery

Do you know how a tiny piece of battery that normally cost a few dollars can bring your high-tech PC screeching to a halt?  this battery is called CMOS or complementary metal-oxide semiconductor. CMOS is just a little battery located on your motherboard, but this is not your ordinary battery that you can find powering your handheld calculators. The first signs that your battery is failing is that your clock started to run slow and you will notice that your computer keeps forgetting the date and time or your computer is having a problem finding and accessing certain peripherals or your PC refuse to boot, displaying a “CMOS Checksum Error” or “System Configuration Lost” message. When you experince those signs it’s time to change your CMOS battery.

Before you jump on replacing your CMOS batter, safety rules first. The inside of a computer is a bad place full of electricity and sharp edges. Make sure that your computer is unplugged from it’s power source. Also be careful on the inside of your computer,  most computer cases are unfinished metal and has very sharp edges.


Here are the following tools you need to change your CMOS battery

1. a X-point screwdriver
2. an anti-static strap(optional but recommended)
3. a new battery (seems logical)

  • First, When you remove the old battery from the motherboard, the information that’s stored in the CMOS will be lost, so you should write down the BIOS settings.
  • Unplug all the cables from the back of the computer, if you are not familiar about the ports at the back of your computer you should make a note  on where they came from so you can easily put them back when your finished.
  • Move the computer somewhere where you can work on it with ease.
  • Remove the cover by locating the screws around the outer edge  at the back of your computer. Some computer cases only require you to remove 2 screws on one side then a panel can be removed allowing you access to the computers insides, others you must remove 6 screws and remove the whole case by sliding it to the rear and lifting it off.
  • Look inside and will see a round silver thing that’s almost a size of bottle cap. Carefully lift the retaining clip and slide the battery out.
  • Back to your computer insert the new battery by lifting the clip and sliding the battery in.
  • Reinstall your case and plug all the cables back (you did remember to label them didn’t you)
  • Power on your computer and check the bios, If you look carefully you will see a line that says something like “press del for setup” or some other key (F2 or ESC or tab) this will take you to god’s house (the BIOS) where you can make lots of changes to the way your machine works.
  • You will now be presented with a blue screen with a lot of options on it, The one we want is load optimised/default settings.
  • Exit and save your bios setting, your computer should now reboot.

If every thing went well then your computer will now be up and running.