PC in re-set loop + CMOS problem

By oakland600
Dec 7, 2006
  1. Hi there,

    Hope someone can help…..

    First problem I had related to the PSU not working properly. The PC kept cutting out on start-up, it was only after pressing the start button/re-set button several times that the PC managed to finally get to the desktop. This problem has got worse and a few days ago during the usual dozen or so attempts at trying to get it started I noticed an error on the first start-up screen (the one where it does the memory check). The error message was:-

    “CMOS checksum error – defaults loaded
    F1 to continue. Del to enter setup/Dual Bios, F9 for xpress recovery

    08/02/2004 nvidia-nforce-6A61BG0MC-00”

    I took the F1 option and it got as far as the windows logo appearing with the scrolling progress bar. The pc then did a re-set by itself but this time there was no cmos error message. However it again did the re-set at the windows logo. So it seemed to be caught in some kind of re-set loop. I switched it off at the PSU as this was the only way I could power it down.

    The next day I couldn’t get it to power-up at all. The PSU had packed in I guess.

    I replaced the PSU with another and on start-up it went into the re-set loop again.

    After a bit of research I replaced the cmos battery from my other PC and tried it again. This time the old CMOS error appeared but this time when I took the F1 option it loaded up windows without any problem. However the processor speed is not appearing correct in the device manager, but I think I know how to fix this in the BIOS/mobo. Unfortunately when I now re-start the PC it goes back into the re-set loop. The only way I can get the PC to boot ok is by taking out the CMOS battery and putting it back in. This only works once and after a re-boot I need to do it again.
    I am actually using the pc now to post this, and it’s been working ok for about an hour, but I know if I re-start I will get the re-set loop problem.

    Can anyone offer any advice?
    Thanks in advance.

    Sorry for the long post.
  2. zephead

    zephead TechSpot Paladin Posts: 1,569

    what are the specs of the machine? the psu?

    try updating your bios and all device drivers you are using, particularly those of the chipset and video card. a PSU that failed as such could have caused data corruption in the ram, which could have corrupted files on your hard drive. also, there is a possibility that the hard disk is going bad.

    whenever i get a machine that behaves this way, i boot to my copy of knoppix (on CD-ROM) and run memtest. if that passes, i boot knoppix. if everything runs fine, you should suspect the hard disk. knoppix is available at but before going through all that i would use memtest. (

    is the hardware being properly detected in the bios? everything come up, as it should?
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