# Solved: Bad check sum message



## mountainrose (Feb 17, 2009)

My husband has a Toshiba laptop with Windows XP. Several times a week, for seemingly no reason, the computer will freeze. Even after waiting a long time, it will not start working, so I have done 2 things--either turned it off with the on'off button or unplugging it for a few minutes. When it comes back on, a black screen with white letters, it has a message: Bad Check SUM (CMOS). Check system, then press the F1 key. Then there is almost a whole page of writing, again black screen with white letters. So I take the cursor and start it at the to, then with the arrow take it down both columns. Then it says to press End, I believe, to save my changes (but I haven't made any changes), then I do that and it comes up with a Y or N to check about really wanting to save it. I'm sure there's something I need to keep it from doing this, but my computer knowledge is limited . Then when that screen comes up, that I just click down, I don't change anything. Thank you in advance for any help you might could give me on any of this. I have a Sony laptop that I recently had a couple of problem concerning it solved on here, so I hope that you can help me with this problem. I really didn't know where to post it, so I hope that this is an OK place for a question like this.


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## Support4U (Jun 29, 2007)

Pls go through the following and let us know what happens 
if u dont follow something pls feel free to ask

*The Error Explained*
The CMOS Checksum Bad Error is an error that occurs when the CMOS values are incorrect. Usually to guard your Bios software, your CMOS memory stores a specific value, each time you boot up your computer this value which is a number is checked against the stored value in the CMOS memory. If these two values are different, it causes an error message. If these values are the same, the computer proceeds as normal.

Each computer usually deals with the CMOS Checksum Bad Error differently. Some computers will warn the user and continue to boot up using settings in the CMOS, other computers might warn the user and then use the default settings in the BIOS as the correct settings and carry on with a normal boot or reboot. Usually, within the error message it will state which strategy your computer has employed.

What Causes CMOS Checksum Bad Errors?
There are usually three main reasons that a CMOS Checksum Bad Error has occurred. They include:

*CMOS Battery not functioning properly *
*Your BIOS has been updated (either by you or possibly a virus)* 
*The computer was shut down improperly (e.g. shutting off the computer's power without first shutting down the computer (MS Windows requires you to shut down your computer before shutting off the power). *

*Situation Remedies*
here are some remedies for each situation:

*CMOS Battery Not Functioning Properly: *
If you suspect your CMOS battery is not functioning properly you can easily change it. Before changing your battery, reboot your computer to make sure that the error still exists. If it does, go into your CMOS and write down all of the settings. If all settings are lost, you can usually get them from your computer manufacturer. Now locate the battery and remove it, you might need to consult your computers manual or tech support to remove your battery. Take down the CMOS batteries information such as volt, size, etc. Once you have your new battery, you can replace it and reenter your CMOS settings. If your battery was the cause of the CMOS Checksum Bad Error, you should have remedied the problem.

*Your BIOS has Been Updated (either by you or possibly a virus): *
If your BIOS has been updated recently, your CMOS settings may have become reset. Make sure that the values entered in the BIOS are correct or simply reset them to the default settings. If you believe that a virus updated your BIOS settings, run a virus scan and make sure that the BIOS settings are back to the default.

*The Computer Was Shut Down Improperly:* 
Sometimes when running MS Windows, if you shut down your laptop or desktop without first properly shutting down your operating system it will corrupt the CMOS settings causing the CMOS Checksum Bad Error. You can easily avoid this error by making sure that you completely shut down your computer before turning off the power. Usually this entails going into the Start Menu/ Turn Off Computer/ Shut Down. If you received the error, shut down the computer properly, if this is the cause of the error, the error message will not return.


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## mountainrose (Feb 17, 2009)

Support4U, I'm a little confused here. I'll tell you what I know from reading the above. First, he does not leave the battery in his computer; is that main battery like we can remove the battery that you are talking about? I do not know the meaning of CMOS or BIOS, so I don't know about the BIOS settings. The only time I have shut it down improperly was when it was frozen and the cursor would not move--I have done it 2 ways, either holding down the power on button or just unplugging it. Those were last resorts, though, when I couldn't get it to go off any other way. When it does come back on, I always have to reset the date and time if that tells you anything.


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## Support4U (Jun 29, 2007)

Yes that means you will have to get the CMOS battery Changed
Its a system battery that keeps your BIOS (_explained below_) ticking even when your computer is shuts down and that is how you have your date and time always correct every time you start computer, this battery can go bad 3 to 4 years at times sometimes may just happen if its loose too, its located within your Laptop on the motherboard. Its like a wristwatch battery but much bigger in size.

*BIOS EXPLAINED*
A BIOS (Basic Input/Output System) is an electronic set of instructions that a computer uses to successfully start operating. The BIOS is located on a chip inside of the computer and is designed in a way that protects it from disk failure.

A main function of the BIOS is to give instructions for the power-on self test (POST). This self test ensures that the computer has all of the necessary parts and functionality needed to successfully start itself, such as use of memory, a keyboard and other parts. If errors are detected during the test, the BIOS instructs the computer to give a code that reveals the problem. Error codes are typically a series of beeps heard shortly after startup.

The BIOS also works to give the computer basic information about how to interact with some critical components, such as drives and memory, that it will need to load the operating system. Once the basic instructions have been loaded and the self-test has been passed, the computer can proceed with loading the operating system from one of the attached drives.


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## mountainrose (Feb 17, 2009)

Ths Toshiba on top says Satellite Pro; one number on the bottom is 6100. Is that the model number? I think I must have said something wrong in my first information. When I turn on the computer and it comes on OK, the date and time are correct. It is only after it freezes and I can't get it off any way but the wrong ways, since the cursor won't move, when it comes back on after that that the date and time are wrong and I have to reset it.


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## mountainrose (Feb 17, 2009)

Where do I clear the history and temp. internet files? About once a week I run the AOL checkup where it goes through defragment.


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## JohnWill (Oct 19, 2002)

I don't think this qualifies as "tech news", I'll move it to hardware.


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## kipper1955 (Feb 23, 2009)

In Internet explorer, go to Tools/Internet options and a screen will appear, In temporary internet files click on delete files, it may take some time, then after that click on clear cookies, then clear history. Up to the individual but I normally do this every day.


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## flavallee (May 12, 2002)

If it's a *Toshiba Satellite Pro*, it should have a series of numbers similar to

####-###### (4 numbers and letters, then a dash, then 5 to 7 numbers and letters)

for the model number.

The Toshiba site lists a range of model numbers for the Satellite Pro from

A200-EZ2204X

to

U400-SP2908R

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## Support4U (Jun 29, 2007)

Hi JohnWill
you are correct, its a hardware issue


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## mountainrose (Feb 17, 2009)

I looked on the bottom, and I could not find any numbers/letters like that. So I went to My Computer, as on my Mac I can find serial number, etc. there, but I didn't know where to go on this one. On the bottom where I found the 6100, there was no combination of numbers like that, so any suggestions?


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## mountainrose (Feb 17, 2009)

Thank you. I thought I was putting it in tech questions! My charges should be astronomical--but look at all the experience they're getting in dealing with a challenge like me! I have a Sony laptop, Mac desktop, my husband has the Toshiba laptop, and I have to try to figure out how to keep the three going--quite a job when you know just enough to be dangerous!


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## mountainrose (Feb 17, 2009)

All evening, I've been trying to find the information asked for about the model number. I have looked carefully at all the stickers on the bottom of my computer, tried to look on the computer information itself, and I cannot find that series or 4 numbers and letters, then dash, then series of 7 numbers and letters. Under Belarc Analysis, I did find this:
System Model Toshiba Satellite Pro 6100 P5610U-JHN849 
Bios. Toshiba Version 1.60 06/12/2002
I even found the User Manual for Model 6100 and I looked at the troubleshooting section, and I couldn't find this problem listed.


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## Support4U (Jun 29, 2007)

hi,
did u try getting the CMOS battery changed


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## mountainrose (Feb 17, 2009)

No, I did not change the battery. I have no idea how to do that. Maybe I should get in touch with the man we bought the computer from. As long as we own it, he will fix it at no charge except for parts, if he doesn't have them. We've had it about 2 years now and haven't needed anything on it until now, but our daughter's or granddaughter's one needed something done, and he fixed it at no charge. He buys computers from a company that uses them for about 2 years, reconditions them and sells them. He prefers Toshibas, and he has lots of parts for them. With our friends and relatives, we know of 8 that he has sold, at $375 or $400, and only two of them have needed any repairs, and he did them as he promised. I don't know why Ididn't think of him before--guess I thought this was something that I could fix myself, so maybe I should call him. Then if something else is wrong, too, he can check it out for us. Doesn't that seem the best thing to do?


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## jazz3000 (Apr 19, 2007)

A CMOS battery is an easy fix and we'll hope that's the issue. If your not familar with how to swap out the battery it's a good idea to take it to someone who can. CMOS batteries go for about 5 bucks. Fingers crossed. Jazz


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## flavallee (May 12, 2002)

Let a qualified tech person change the CMOS battery in a laptop, unless you're technically challenged to do it.

It's much easier and safer to do it in a desktop.

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## mountainrose (Feb 17, 2009)

Thank both of you for your advice. Since I know nothing about doing this, I think that I shoud call Kent, the man I bought the computer from, about this. I don't attempt any repairs; I had just hoped that this would be a simple fix. So you have both been a big help to me on this. I will let you know what happens when I talk to Kent. I hope to be able to get him tonight. I love my computers and all that I can figure out how to do, but I am overwhelmed when something happens that I cannot fix, so I really do appreciate both of you for having the patience to work with me on all my problems so far! I will let you know what happens with this problem, and I may need to post more on this site! I'm going to mark this solved, because as far as what you can do, since I cannot fix this battery, you have solved it because I know that I must call a professional.


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## flavallee (May 12, 2002)

:up:


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## mountainrose (Feb 17, 2009)

Good news and bad news about computer. Good news--I talked to Kent tonight, and we are taking my husband's Toshiba to him tomorrow for him to check it out and see if he can fix it. Bad news--he has taken a new job and is moving to Shreveport, LA, in about 10 days! So hopefully he can get the computer fixed now. If we need him after this, we will have to mail it to him! A friend of ours who lives in Michigan had a problem, mailed computer to him, and he fixed it at no charge. Will let you know what happens with this next step. Thanks again to both of you for helping!


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## Support4U (Jun 29, 2007)

Hi Mountainrose,
so nice of u to keep us updated about the laptop, hope it gets repaired soon. if thr is anything do let us know.


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## mountainrose (Feb 17, 2009)

Today's update. I ran the Toshiba by an office supply for a free computer check. Basically they said it could stand a tune-up and maybe that battery should be replaced. They said that it had 25 things on start-up and a lot of them should go. Anyway, mixed in with his packing up his family to move, Kent will set aside time one day next week for whatever it needs, and hopefully he can get it to working OK. I am also taking him my Sony laptop, as something is not right on it. I have Clearwire for my Internet service, and both the Toshiba and my Mac sign on to AOL in about 30 seconds, so I know it's not Clearwire. My Sony laptop will take from 5 minutes to 30 minutes, which is quite exasperating. So maybe he can do something there. I have it in my dining area where I can use it in the den/kitchen/dining area, all one large room, and after I turn it on, I can sometimes go fix a whole meal while it's doing whatever it does. I want Kent to fix all he can before we lose him! After Kent's checking it out, I will give you hopefully a good report. I don't know if you can answer this for me on this section, but what better would you recommend than Norton and Spyware Detector? I have both on Toshiba and Sony. I don't have anything on Mac--any suggestions there? Again, thank you all for helping me.


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