# [SOLVED] unable to access cmos setup



## efran (Mar 23, 2011)

Hi, i'm hoping someone could offer me a little with my situation. I have the following: MOTHER BOARD – P4M900-M4 (P490M828 BF)
When I start my system I get the following message: Floppy disk(s) fail (80)
CMOS checksum error – Defaults loaded
Warning! CPU has been changed or CPU Ratio changed fail.
Please re-enter CPU settings in the CMOS setup and remember to save before quit!

When I press F1 or DEL, F8 or F9 nothing happens. The lights flash on the keyboard but the NumLock light will not stay on or come on when I press. Here is what I have done so far: I have removed battery, I have changed jumper from 1-2 to 2-3 for five seconds, I have tried the keyboard in ps/2 and in the usb port.

Am I missing anything or is there some other thing I can do that I haven't done to this point?

Thank you for any help.

efran


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## Tumbleweed36 (May 14, 2005)

*Re: unable to access cmos setup*

Remove the motherboard battery for a few minutes and then replace it and give it a try. Make sure you unplug from the wall first, and ground yourself before you get in that case. Report back to us.


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## efran (Mar 23, 2011)

*Re: unable to access cmos setup*

Thank you for the reply. I removed the battery as you instructed. It was out for about 10 minutes, however, it still didn't resolve the issue. I have attached a photo of the screen post. Pressing the del, f1 or any other keys have no affect during or after the post.

I'm going to call it a night. Will check back in the morning for other possible solutions.

Thanks for your help.

efran


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## Tyree (May 10, 2009)

*Re: unable to access cmos setup*

Try disabling the Floppy in the Bios. Then clear the CMOS using the jumper and see how it goes.


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## efran (Mar 23, 2011)

*Re: unable to access cmos setup*

i cannot get into any settings to disable anything. the screen just posts and that's it.


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## [email protected] (Nov 16, 2004)

*Re: unable to access cmos setup*

Just a couple thoughts, after unplugging the box and removing the CMOS battery for 10 minutes, you should also press & hold the power button for 10 secs.

Next, I wonder if there isn't a bug in the BIOS firmware that would require you to press the 'DEL' _during_ POST instead of waiting until that informational screen shows up. Stranger things have happened. Try poking the DEL key every 1/2 sec. during POST.

Perhaps leave the keyboard as PS2 until you have a resolution (many mobo's have trouble recognizing a USB keyboard during POST).


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## efran (Mar 23, 2011)

*Re: unable to access cmos setup*

Thanks once again for your reply and suggestions.

I tried every suggestion in the last post to no avail. In addition I tried the following. I left the battery out and tried to start the system. It would not even power up. I attached a floppy drive to the motherboard and that did nothing. I didn't even see the power light come on on the the floppy drive but i'm not sure if it would even display during boot anyway.

Unless there are still suggestions for me to try, eventually my next step will be to benchmark the mobo and bare bone it and test it step by step.

Really it seems there is no communication between the keyboard and mobo. As I indicated earlier the keyboard lights flash during boot but numlock key light will not come on when I press it.

Thanks again everyone for your help so far.


efran


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## dai (Jul 2, 2004)

*Re: unable to access cmos setup*

what are you running
video card
cpu
m/board
ram
power supply
brand
model
wattage

cmos chksum error can come from a failing or underpowered power supply


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## [email protected] (Nov 16, 2004)

*Re: unable to access cmos setup*

At this point I agree that you should do the benchtest setup. I'd also try a different keyboard.

Also, I'd remove the CPU, inspect, clean - paying particular attention to the sockets the CPU pins go into since even a single hair or dust mote can shut a computer down; re-goop with new heat sink compound, and reinsert it. Then open/close the locking lever several times. Plus clean it's fan and heatsink.

How can a socket cause problems after it's been working fine for years? Heat-cooling cycles can slowly open a socket and allow accumulation of dust that eventually causes a simple open circuit of a CPU pin.

My fingers are crossed that that's your only problem. Odds are 25% I'd say. JMO. :wave:


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## efran (Mar 23, 2011)

Hi Dai,
This is my motherboard: BIOSTAR :: P4M900-M4 :: Specification
Video card is built in, cpu-intel pentium 4. Power supply is Ezmax model: YH-480W. I've used a few different power supplies.

[email protected], i've completed a benchtest with monitor, keyboard and i'm still getting the same results. I removed the battery and ran the system without it to rule out bad battery, no change. (May get a new battery anyway). I've used several different keyboards but the same thing happens. One thing I noted, I totally removed keyboard, removed jumper from 1-2 to 2-3 for about a minute and back again and removed battery for ten minutes and replaced. I left the keyboard unplugged thinking it would give me the "halt on keyboard" error with the "press F1" to enter setup. The post went straight through without any keyboard errors to the original error. 

I did remove the cpu and reseated it again following your instructions. Inspected it carefully. I did notice it had very little heat sink compound on it. I added more. Didn't change the results. 

Thanks everyone for your help.


efran

**RESOLVED**
This issue was caused by a malfunctioning power supply. All is well now. Thank you everyone who tried to assist with issues.

efran


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## dai (Jul 2, 2004)

*Re: unable to access cmos setup*

glad you have it sorted


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