# [SOLVED] Bad BIOS Checksum



## casals (May 30, 2008)

On switching on I get the message Bad BIOS checksum. Starting BIOS recovery. Looking for floppy disc - can't find etc. I Changed BIOS battery but problem remains. I had to change the motherboard for a second hand ASUS one about 9 months ago. Do I need to use the recovery floppy after changing the battery? Any help much appreciated.:upset:


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## mack1 (Nov 27, 2007)

*Re: Bad BIOS Checksum*

Hi casuals and welcome to TSF:wave:
You will probably have to download the latest BIOS from the motherboard manufacturer's web site. Besure to get the right one for your board. Normally it can be loaded onto a floppy and flashed from there. A dos like program can be downloaded to install it. You might get it with the BIOS file when you download it. If not, look for it at the same site. It is simple and straight forward to use. Just for safety sake, save the old BIOS before installing the new. 

A checksum is a method of checking the integrity of a file (BIOS in this case). It adds all the bytes together and compares it with a checksum previously recorded at the end of the file. If they don't match, something has changed, thus corrupted data. 

Hope this helps:smile:
Mack1


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## casals (May 30, 2008)

*Re: Bad BIOS Checksum*

Hi mack1 & thanks for the prompt reply. Went on the ASUS site & they don't seem to have the PAP800 socket 478 865PE X se vm deluxe. (it's called P4P800 on google results. I went by the receipt as I can only find the word ASUS on my motherboard.) Maybe it's too old for them to provide updates. Do you know of any other sites that might have it? casals london UK:smile:


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## belfasteddie (Aug 4, 2007)

*Re: Bad BIOS Checksum*

Try pressing Alt+F2 at Bootup. I don't know how old your board is but that is what my Asus brd requires.


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## casals (May 30, 2008)

*Re: Bad BIOS Checksum*

Thanks for advice but I'm afraid it doesn't help. I've found a site with a suitable beta BIOS download. Unfortunately it links me to ASUS whose site is down for repairs!


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## mack1 (Nov 27, 2007)

*Re: Bad BIOS Checksum*

Hi casuals,

Pulling the battery only resets the BIOS, and don't require anything special to boot after that if the default BIOS data is OK. 

There may be some places on the web to download bios files, but I don't have any first hand knowledge about them. You may have to just wait until the Asus site is back up.

Best regards,
Mack1


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## dai (Jul 2, 2004)

*Re: Bad BIOS Checksum*

uou can lso get this when the computer is underpowered


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## casals (May 30, 2008)

*Re: Bad BIOS Checksum*

Thanks mack 1 & Dai Sorry didnt reply sooner. Fixed prob finally & have switched back to this PC. Removing the jumper & replacing it did the trick. Wasnt sure which jumper to remove at first. Not labelled CMOS just CLR. While looking for a fix someone reported RAM sticks causing this so I moved them round & all kinds of probs started. So though Id fixed initial problem Id created new ones in the process. Anyway its stabilised on 1 250 MB stick at the moment but very slow & I've just ordered 2GB of Crucial.:wave:


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## mack1 (Nov 27, 2007)

*Re: Bad BIOS Checksum*

Hi casuals,

Glad you got it going. You will really notice a difference with 2 gig of memory.

Best regards,
Mack1


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