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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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
35 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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after replacing ,cmos battery , computer won't boot

I got error Cmos battery failure Cmod checksum error I replaced the battery When I power on, only power light and fan are working Monitor is " no signal". Hard disk indicator stay steadily on for 4 ...
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83 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
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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
87 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
48 views

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

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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24 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
103 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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1answer
71 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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16 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
85 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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1answer
71 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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27 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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1answer
640 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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111 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
88 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
83 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
41 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
2k 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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0answers
80 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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19 views

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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32 views

acer aspire z5600 erratic screen issue

Can;t select time zone; screen drop panel will not go to the bottom; can't select time zone; whatever I would select when successful is ignored; in troubleshooting, decided it could be my cmos ...
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1answer
33 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
45 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
399 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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190 views

cmos jumper location on a toshiba satellite p75-a7200

Where is the cmos jumper located on a Toshiba satellite p75-a7200 laptop computer? I have taken out the battery but can not find where the cmos jumper reset is located on the motherboard.
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2answers
169 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
142 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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0answers
149 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
315 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
161 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
169 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
536 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
262 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
360 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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0answers
295 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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3answers
9k 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
107 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 ...
2
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1answer
256 views

What is the rationale behind the default values for adjtimex --adjust?

The adjtimex utility has an --adjust mode that can be used to compare the system clock with the CMOS clock, calculate suggested values for the tick and frequency offset kernel time variables, and ...
2
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0answers
425 views

PC won't start unless I reset CMOS

Situation: My PC is dead in the water. Both power buttons (Case/MB) have no effect. If I pull the power cable, reset CMOS, reconnect the power cable, then press either power button the PC fires right ...
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3answers
74 views

BIOS settings changed unexpectedly

Here's what happened: Desktop working perfectly (playing SuperTuxKart on Linux Mint). Power down (computer left unattended, no one home). After about 3.5 hours - power up. Linux Mint starts up ...
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1answer
303 views

How to REALLY enter setup on ASUS K75DE?

I really have no idea what's going on here. I have an ASUS K75DE and both official manual and the official site says the Setup key is F2, however no matter how fast I smash the key constantly, nothing ...
3
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2answers
5k views

What does this beep code mean?

When I wanted to start my laptop today (an Acer Aspire 8920G), the laptop started beeping. I know this beeping is a POST error code, but I can not figure out which one it is. The motherboard of the ...
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3answers
4k views

Can't get into CMOS setup on MSI MB 970a-g46

I can't seem to get to bios any more. barely see the MSI logo flash by, no setup message that I see that I've read about. The delete button is access to it. This is an MSI 970a-g46 motherboard, ...
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120 views

Checksum Bad error on boot

Recently I inserted a new 2GB ram in my motherboard, and got Checksum Bad error on bootup. Upon reading other forums I assumed my CMOS battery must have been dead. I replace this with a new one and ...
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4answers
1k views

CMOS Battery recharged [duplicate]

My pc was unused for several months(its a 5 year old acer desktop) and on boot up a screen came up indicating that the CMOS battery was low. Any time I restarted, as expected, the same screen came up ...
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1answer
2k views

What is a “cmos checksum bad” error?

Two days back when I booted my system up, it was showing a screen with a bunch of messages and instructed to press F12 to continue booting. Two times it showed up when I booted my system and now it ...