Is BIOS flashback button important?

comcom said:

What is the proper way of changing CMOS battery?

I assume the procedure is switch off PC>remove CMOS battery>insert new CMOS battery>switch on PC?

Do you need to go into BIOS to do anything?

Remove the old battery. Wait a minute or so to ensure the BIOS is cleared then insert the new battery. I always check the battery voltage even for a new battery - it should be c. 3.2V. Start the PC then enter the BIOS and load the BIOS defaults. You will probably have to set the time and date. Save the settings and reboot. You can then enter the BIOS again if you wish to modify any settings.

comcom said:

How do you load the BIOS defaults? Select/press where in the BIOS?

I am assuming once you remove the old battery, the BIOS will lose all modifications and automatically revert to defaults, when a new battery is inserted it will auto load BIOS defaults, correct me if I am wrong.

You can't assume that will happen. Usually there is BIOS option under Load / Save to load the BIOS defaults. Check your user manual.

Steve C said:

Not true. The CMOS battery failed in my previous desktop PC having a Gigabyte motherboard about every 2 years. It would fail to boot if the voltage dropped much below 3V. I do keep my PCs powered off at the mains when not in use.

Mileage varies i still have desktops from 2008 that have the original battery, i have seen computers earlier than this with same battery still. They can die quicker than others.

comcom said:

How do you load the BIOS defaults? Select/press where?

I am assuming once you remove the old battery, the BIOS will lose all modifications and automatically revert to defaults, when a new battery is inserted it will auto load BIOS defaults, correct me if I am wrong.

Yes the CMOSS requires power to keep its settings, if the computer loses AC power the battery is there to keep power to the CMOSS so that it does not lose it settings.

comcom said:

I am wondering why is there a need to load the BIOS defaults?

If the BIOS settings was working fine before changing the battery, if after changing the battery the BIOS continue to load the same BIOS settings (settings that was done before changing the battery) I would assume it would be fine and could save some time redo any BIOS settings, correct me if I am wrong.

There is no reason to reset the settings on a battery replacement. If you take the batter out with the mains power still plugged in then it should keep the settings.

The only time it would reset the settings is if the mains power is removed before the battery is.

@comcom


Ok let's see...

On ASUS motherboards, and most others... there is a "Tools" tab.
On there, you should be able to "save" your BIOS settings to a "profile".

CMOS batteries - Ancient Wisdom...

1. For a dead or dying CMOS battery, any number of weird things may have occurred. It'll be like the BIOS is getting senile.

2. This is why it's a good idea to either restore your BIOS settings from a profile or manually. Just to be sure all is OK.

3.. Sometimes, when over clocking, maybe... the computer won't boot. So you need a way to "reset" the BIOS and start again.

4. You can reset the BIOS to optimized "defaults" on the "Exit" tab in the BIOS.

5. Sometimes the BIOS will just glitch. Maybe a power failure, maybe an act of god. When that happens, you want to restore your BIOS settings from a profile, or just reset the BIOS to defaults via the Exit tab.

6. Sometimes the BIOS causes problems and you can't get INTO the BIOS to fix things. In these cases... you can either pull the CMOS battery, or use the BIOS reset jumper.



The CMOS battery allow the BIOS to "remember" it's settings, even if the computer is OFF. This is why they sometimes need replaced. They hardly ever need replaced... but you know what they say.... sometimes things just happen.

If you need to pull the CMOS battery to reset the BIOS... then you have to do it a certain way.
1. Turn the computer OFF, and turn OFF the power supply switch.
2. Leave the power supply, plugged into the wall outlet, and hold the case's power button pressed for about 10 seconds.
3. THAT will discharge any motherboard capacitors which may still be holding power.
4. THEN... take out the CMOS battery, wait about 5 minutes, and put the battery back in.
5. Now... the BIOS should be reset to defaults, and you should be able to get INTO the BIOS to do whatever is needed.


The CMOS battery is a CR-2032 battery and should be 3.2 volts. You can get them in drugstores, Walmarts, etc. They cost about $6-$8 dollars.
The reason the batteries are shaped the way they are... is because, before computers, they were wrist-watch batteries.

Now, you're a CMOS battery expert. Bookmark this post for future reference, or Print it for safekeeping.


Last but not least... the time and date in the BIOS "must" be the same as that shown on your computer clock.
If they aren't... Windows and some 3rd party programs, will start losing their minds.
This will happen mostly to things with licenses or product keys, that put time/date entries in your registry when installed.

Ghot said:

@comcom


Ok let's see...

On ASUS motherboards, and most others... there is a "Tools" tab.
On there, you should be able to "save" your BIOS settings to a "profile".

CMOS batteries - Ancient Wisdom...

1. For a dead or dying CMOS battery, any number of weird things may have occurred. It'll be like the BIOS is getting senile.

2. This is why it's a good idea to either restore your BIOS settings from a profile or manually. Just to be sure all is OK.

3.. Sometimes, when over clocking, maybe... the computer won't boot. So you need a way to "reset" the BIOS and start again.

4. You can reset the BIOS to optimized "defaults" on the "Exit" tab in the BIOS.

5. Sometimes the BIOS will just glitch. Maybe a power failure, maybe an act of god. When that happens, you want to restore your BIOS settings from a profile, or just reset the BIOS to defaults via the Exit tab.

6. Sometimes the BIOS causes problems and you can't get INTO the BIOS to fix things. In these cases... you can either pull the CMOS battery, or use the BIOS reset jumper.



The CMOS battery allow the BIOS to "remember" it's settings, even if the computer is OFF. This is why they sometimes need replaced. They hardly ever need replaced... but you know what they say.... sometimes things just happen.

If you need to pull the CMOS battery to reset the BIOS... then you have to do it a certain way.
1. Turn the computer OFF, and turn OFF the power supply switch.
2. Leave the power supply, plugged into the wall outlet, and hold the case's power button pressed for about 10 seconds.
3. THAT will discharge any motherboard capacitors which may still be holding power.
4. THEN... take out the CMOS battery, wait about 5 minutes, and put the battery back in.
5. Now... the BIOS should be reset to defaults, and you should be able to get INTO the BIOS to do whatever is needed.


The CMOS battery is a CR-2032 battery and should be 3.2 volts. You can get them in drugstores, Walmarts, etc. They cost about $6-$8 dollars.
The reason the batteries are shaped the way they are... is because, before computers, they were wrist-watch batteries.

Now, you're a CMOS battery expert. Bookmark this post for future reference, or Print it for safekeeping.


Last but not least... the time and date in the BIOS "must" be the same as that shown on your computer clock.
If they aren't... Windows and some 3rd party programs, will start losing their minds.
This will happen mostly to things with licenses or product keys, that put time/date entries in your registry when installed.

My new Asus X570 board clears the profile on updating the BIOS so you can't use that method. You can store the settings to a .CMO file on a USB drive but that is unreliable too. I just updated my BIOS last week and the BIOS screen would hang as soon as values were loaded from the .CMO file from the previous BIOS. I had to configure my settings manually. Fortunately I had written them down.

I once had a BIOS problem to a power on glitch and had to reflash the BIOS. CR2032 batteries are far cheaper than $6 from Amazon wtc.