# CMOS checksum bad???



## klingon (Jan 19, 2011)

I spent 14 years working in IT support, and 5 years ago made a career change to be a locksmith. I'm a little out of it and need some help.

Product: HP Pavilion dv6000
O/S: Was Vista, started trying XP Pro.
Issue: When I turn the power on, the laptop stays on for about 25 seconds, then reboots. Over and Over and Over. I never see anything on the screen at all.
Attempted Resolution: I started nailing the del button at startup, and about 1 out of every 10-15 times I'll hit it just right and I get into the bios settings. Made a few changes to no avail. I save and exit, and the computer boots up normally. Works perfect until I have to reboot. I can tell you it was quite a long process trying to reload Windows having to do this at every reboot. (I tried using XP instead.)
Next Attempt: I started alternating between f10 and del, and I was able to watch the POST. All looks normal until after I reach "Mouse Initialized". Here is what I get:
ERROR
0271: Check date and time settings
WARNING
0251: System CMOS checksum bad - Default configuration used.
Press <F1> to resume, <F10> to Setup
I go to Setup, the date and time are still correct, I save and exit, and I boot normal. I even pulled out the CMOS battery, and I still have the correct date and time. But, it can be a half hour ordeal trying to get through all of this.
If you can offer some help to a former IT fella, I'd appreciate it.
CJ


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## [email protected] (Nov 16, 2004)

Does it stay on if you leave the computer in BIOS?


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## klingon (Jan 19, 2011)

Yes. Laptop stays on in setup mode.


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## klingon (Jan 19, 2011)

Once it boots, it stays on perfectly. Works great. Once I reboot I'm back in the same situation. Thanks for your help. It's driving me nuts.


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## [email protected] (Nov 16, 2004)

OK, let's see what we can do.

The fact that the date and time stayed the same indicates you didn't unplug the laptop from AC or remove the main battery. Do both. Then remove the CMOS battery, wait 5 minutes, press and hold the pwr button for 10 seconds. Then reinstall the CMOS battery. Then install the laptop battery, and plug into AC.

Then go into BIOS during POST, and reset the date and time. Save and allow to boot. What happens?


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## klingon (Jan 19, 2011)

Doing this right now. Will advise. Certainly appreciate it.


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## klingon (Jan 19, 2011)

Did as you instructed. I unplugged CMOS battery, then laptop battery, then AC. Waited. Held power button for 10. Reinstalled CMOS battery, laptop battery, and plugged in. Turned on. Had same issue of having no display at all. Caught it with the del key on second try and went to setup. Time and Date had reset to 2006. Set correct time. Saved and exited. Same issue. Boots over and over and over every 25 seconds or so with nothing onscreen.

Really appreciate the help.
CJ


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## [email protected] (Nov 16, 2004)

Well, at least we know now that the BIOS is functioning correctly. You can go into BIOS and set it to display the long BIOS display sequence (usually, if not always). The lack of a manufacturers splash screen is often called a 'short boot'. The long boot displays info about attaching to hardware (like the drives and a memory scan). The repeated boots generally indicate a fault with hardware. So at this point, I'd set BIOS for the long boot, and remove any external devices, like USB drives, network cables, phone cables and the like. And remove any optical drives.

BTW, you know you can press 'Pause' just before the reboot and see what's on the screen? Might be a message there.

Although it can be hardware, and that's what I'm trying to eliminate, it's also possible that there's a HDD boot sector issue that throws it back to the BIOS as soon as it hits the faulty software issue.

Can you try pressing F8 to get to the XP boot screen? Multiple times just as the BIOS finishes? And choose 'Safe Mode'? What happens then?


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## klingon (Jan 19, 2011)

Will try what you suggest. One update:

I did what you instructed the first post. Now, I am avoiding the del/f10 button scramble and just letting it do its thing. After about 5 reboots, I finally saw the HP splash screen, and it booted fine into XP. I rebooted again, and on the 4th attempt, it came up fine again. I rebooted once more, and it took 10 more times of rebooting itself and it finally came back up.

Hope this helps. I would love to get this thing working so the kids and I can stop fighting for time on the web. 
CJ


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## [email protected] (Nov 16, 2004)

Oh, cool, an intermittent issue with randomness. Not the easiest to solve. Why not just leave it run between repair attempts? Not every problem needs to be solved right now. In other words, next time it boots into XP, just log off when the kids are done and leave it running.


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## klingon (Jan 19, 2011)

Will do. I'll have to turn off the hibernate I guess. I left while eating dinner, it went into hibernate, and boom. I'm back waiting for it to decide when to let Windows take over. Any thoughts on that?


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## [email protected] (Nov 16, 2004)

Only to turn off 'hibernate'. Other then that, nothing comes to mind.


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