CMOS (stands for complementary metal-oxide-semiconductor) is a type of technology used in the manufacture of integrated circuits which include elements of digital logic.

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What used to happen when the non-rechargeable CMOS battery ran out?

I'm taking a uni course on electrical engineering and my textbook says that the CMOS battery used to last between 2 and 10 years. Since preserving BIOS settings seems quite important to me, I was ...
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17 views

Motherboard not providing output or giving beeps

This is an email I sent to the ASRock motherboard company's support email address. My motherboard will power my heatsink fan, my led's, the powerbutton, and even my SSD. I am getting no output from ...
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25 views

Motherboard won't boot up after windows 10 network driver installation

So after installing windows 10, the computer was working fine and I was able to use it and all but when we went to install the network driver for windows 10, it froze and then turned off. I've got ...
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60 views

What else can cause PC clock delay, if CMOS battery and RTC module seems OK?

I have a Acer Veriton N260G Series PC nettop with motherbord labelled as All In One Motherboard GN40S01-1.0-KSH GN40S01 or All In One Motherboard MB.VA309.002. Computer's clocks is getting very late ...
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1answer
159 views

What does a CMOS chip look like?

I'm trying to figure out the difference between BIOS and CMOS. I always thought the BIOS setup was software installed onto the CMOS chip. According to this video, the BIOS and CMOS are both chips. ...
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75 views

Why do I have to remove the CMOS battery each time I start the computer?

Yesterday I replaced my CMOS battery with a new one. After that I turned on my PC, then my cooling fans and hard drive started up, but my monitor wasn't showed anything, only a blinking monitor ...
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27 views

Laptop CMOS battery implications

My 4 year old Dell Inspiron 15R's CMOS battery is running out (has run out ?). I know this because when I turn the laptop on it keeps on giving me 5 beeps till Windows loads. I am sure replacing the ...
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57 views

PC either won't boot or has a delayed boot after Windows 8 factory restore

Gateway DX4870-UR368 14 GB Ram Windows 10.....then Windows 8 Core i7 3770k This nightmare started this past Friday night. I was installing a (legit) music production program from the DVD drive when ...
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669 views

Windows 10 time falling an hour behind

I've checked and my BIOS clock stays correct so it can't be the CMOS battery. Also when I boot Windows 10 and the clock is an hour behind if I got and sync the clock with the time server it shows ...
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0answers
174 views

Fujitsu lifebook s752 BIOS password removal

I am trying to remove the BIOS password on a Fujitsu lifebook s752. Trying to remove it by getting a master password and using dogberts algorythms is impossible as it gives me back a 24 digit hash, ...
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1answer
58 views

Low CMOS battery but it's brand new [closed]

When booting my old PC it says low CMOS battery so I replaced it with a spare battery which I bought a few years back. Upon booting from power-off state, it still says low CMOS battery. Is it ...
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1answer
100 views

Average lifetime of a RTC (Real-Time Clock) on a motherboard? [closed]

I have a series of computers in the company I work for that all suddenly started to lose track of time and start falling behind a few seconds to a minute in terms of system time (until Windows ...
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2answers
261 views

Motherboard keeps giving checksum error after installing new battery

I am repairing a computer with an ASUS M2NBP-VM CSM ACPI motherboard (I am not sure this is the correct description of the motherboard but, at least, this is what gets printed to the screen during ...
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1answer
134 views

What defines a CMOS checksum in a BIOS system?

I am sure that many of you have seen and experienced the dreaded "CMOS checksum error" first hand. But what is it? CMOS Checksum error What is it a checksum of? The entire content of the CMOS ...
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158 views

Flashing BIOS using an external SPI programmer

Has anyone succeeded with BIOS flashing using an external SPI programmer ? I saw some cheap serial flash spi programmers on eBay for very cheap price such as $3. (CH341A based programmers) I was ...
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2answers
3k views

When I hit DEL during start up, am I entering CMOS or BIOS?

For the longest time I assumed I was entering the BIOS setup and CMOS is a chip that holds the settings I set in BIOS in its memory. I recently read somewhere that when I am configuring the boot ...
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3answers
9k views

Why do PCs still require a CMOS battery?

Why do PCs still require a CMOS battery, given that they're already plugged in? We are providing lots of power to the PC by plugging it into AC mains electricity, so why does it still require a CMOS ...
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3answers
139 views

Unable to access my BIOS although the OS boots fine

I have an MSI GT602OC Laptop upon which I'm using an Ubuntu 15.04 (only OS). I can access my OS, it boots fine, no problems here. But when I try to access the BIOS (through the DEL key that I used ...
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2answers
75 views

What exactly is present in CMOS when system is turned on for the first time? [closed]

Also, how does the CMOS get all the hardware information/parameters and store them?  Does the BIOS write them into the CMOS or some other hardware? BIOS has the facility to do POST. Is POST somehow ...
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30 views

no power after resseting cmos?

My computer wouldn't let my usb keyboard work on boot and i could not access BIOS. So, i did what i usually do and remove the battery from the mobo and put it back again.At first, it would turn on but ...
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1answer
409 views

BIOS of Dell R410 resets for no good reason

We run a Dell R410 server. The trouble we are facing is that it does not remember it's BIOS settings. The pain in that is that we need to be physically at the server when it reboots. Let me list some ...
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2answers
151 views

SSD with Bitlocker not booting after CMOS being cleared

I have a HP Envy with Windows 8 installed on a SSD. The drive is encrypted with BitLocker. Today, I disassembled my laptop to clean the fans. After putting it back together and turning it on, I got a ...
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25 views

Keep having to reset BIOS for computer to function

I have a year old computer that keeps just showing a black screen. As in there is nothing being sent to the monitor. Upon taking out the CMOS battery to reset the bios it works again however it only ...
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1answer
354 views

How to clear CMOS on a Asus TF810C tablet?

I have an Asus TF810C tablet which won't boot. I thought about doing a Clear CMOS, but the manual doesn't tell how to do it and doesn't even have troubleshooting section. This is the first time I ...
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321 views

Trouble booting after replacing CMOS battery

After replacing my CMOS battery today, I initially got the expected BIOS warning that the CMOS settings are wrong in that the time was off. After I set the time, I had the BIOS save the updated ...
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30 views

Lenovo t400 s7 cmos

Hi my battery is dying dead and now my ac power is intermittent. It will start and run on ac and battery for a few hours but dies. It will not run on ac alone, although the power light flashes. Now ...
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2k views

Asus X99-Deluxe - Can only boot with the “Clear CMOS” button after cooler installation

It sounds like I have similar symptoms to this question, but this only started happening after swapping out a heatsink for a cooler. To be precise, the system will only boot if I press the clear CMOS ...
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238 views

Some CMOS Settings Not Retained on Reboot. Battery good

Some CMOS Settings Not Retained System: Dell Inspiron 546 Motherboard: DELL F896N 0896N Experience: Advanced Issue: Some CMOS settings are not retained after saving and reboot. Some CMOS / BIOS ...
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1answer
298 views

How can I find the cause of a system freeze recurring after CMOS battery change?

My family's computer is freezing every time it is used, ever since I changed the CMOS battery. I've tried many things in vain, and I don't know what to do anymore. I'm looking for theories and a fresh ...
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1answer
177 views

PC Stuck on verifying DMI pool - taken many steps

I have an old computer I am attempting to restore. It's a msi 945g series chipset board. I began with no POST beeps and no monitor signal being detected. I have.... Removed, Cleaned and Reseated ...
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1answer
91 views

Forget previous employers domain

How can I get my laptop to forget the domain of my previous employer? This user account seems to be running some sort of batch file (which I can't find) to connect up to network drives and printers ...
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3answers
4k views

“Please enter SETUP to recover BIOS setting” message on boot

When I boot the PC it gives the following error: Please enter SETUP to recover BIOS setting Press F1 to run SETUP Press F2 to load default values and continue I have tried to set these ...
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126 views

CMOS battery issue

The 5+ year old CMOS battery in my PC died and the BIOS lost it's settings. I replaced the battery but the same problem persists. As soon as I plug the PC into the power outlet, I get 4 beeps ...
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Is there a way to find out how many memory cells on a SSD are broken [duplicate]

A Solid-state drive consists of Flash-EEPROM (electrically erasable programmable read only memory) which is is build up of FGMOS (Floating-Gate metal–oxide–semiconductor field-effect transistor). With ...
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1answer
39 views

CMOS settings failure on every power on

I'm getting "corrupt CMOS settings" message on every power on. Tried to replace the CMOS battery with new one, it didn't help. Ideas?
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1answer
59 views

Changing CMOS battery on Dell Optiplex 280

I have an old Dell optiplex 280 and its cmos battery just died. Please can someone tell me if I change its battery the bios will be lost? or only the bios settings will be lost (which are already lost ...
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1answer
546 views

CMOS checksum error after upgrading BIOS and clearing CMOS

The system is a Gateway DX4831-3, with a MB.GAJ09.001 motherboard. The updated BIOS is revision P01.B1, downloaded from Gateway's website in the support/drivers section. I was able to flash the BIOS ...
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2answers
258 views

How the PC boots even after the CMOS battery failure?

Whenever I do switch on, my pc boots straightaway. It doesnt wait for me to press the Power button. When I plug the cable and power on, computer also automatically gets powered. So I replaced the CMOS ...
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2answers
183 views

How to fake having a CMOS battery for RTC

I have an embedded computer running Ubuntu Server 14.04 that has no CMOS battery (temporary, I hope) so it always boots to December 31, 2008 ... Currently I'm developing an application that depends on ...
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233 views

Laptop losing time when shut off

I have a laptop with Win 7 that is losing time. The laptop's battery has been lost and so the laptop works when plugged in. The time displayed by Windows continues ticking forward at the desired pace ...
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1answer
618 views

Where is the CMOS setup utility stored?

I am reading an old A+ certification book that is going over BIOS and CMOS. Some background info (this may all very well be incorrect): From what I understand, BIOS is a set of programs on the ...
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2answers
289 views

Is it possible to brick a computer due to corrupted CMOS?

Does the BIOS do error checking before booting with the CMOS configurations? Or does it blindly take whatever inside the CMOS and try to boot with it?
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1answer
278 views

CMOS editor on Windows?

I need some way to modify BIOS settings in the CMOS memory from within Windows. Particularly I want to change the "state after power failure" setting through a remote VNC connection. Mainboard: ASUS ...
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3answers
1k views

Is clearing CMOS and flashing BIOS same operation?

My friends' desktop PC won't boot, shows nothing on display, confirmed that everything's working fine, but BIOS is corrupted..need to flash the BIOS using bootable CD/USB (Hiren's boot CD or Ultimate ...
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2answers
385 views

CMOS failure MSI motherboard

I recently tried to get an old MSI P965 Neo motherboard working, but the cmos is getting cleared every time i boot the pc. I tried a new 2032 3v battery, but it still wasnt working. I can get into the ...
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1answer
585 views

What are the negative effects of a flat CMOS battery?

Recently I have noticed that my computer has been starting up with the time and date incorrect. Given that my motherboard is about 7 years old I'm guessing that the CMOS battery is flat (or close to ...
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415 views

CMOS battery lifespan

How long does it take for a CMOS battery to STOP working since the first instance of a failure. For example, if a CMOS battery fails on Jan 1, but then works without problem until May 1 (four months ...
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4answers
14k views

Forgotten BIOS supervisor password--Lenovo B570

I've tried everything possible to reset the supervisor password on my Lenovo B570 laptop: looking for a non-existent CMOS battery, trying to run some of those software tools that are supposed to give ...
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0answers
113 views

PC Black Screen After BIOS Screen?

I booted my PC and after the BIOS screen which says F12 for bios setup and all the other options, I get black screen. I can't access bios options because when I press the button, it just shows me ...
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1answer
1k views

I have dell inspiron 545 desktop. It won't start up unless I remove the bios battery

I have dell inspiron 545 desktop. It won't start up unless I remove the bios battery. The issue first appeared 2 days ago. I left computer a few hours and when I got back the screen was black,lamp ...