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  1. #1

    Default "Disk boot failure" and FDISK /MBR Command

    My Windows 98SE system sometimes doesn't boot up properly and hangs on the screen message "Disk boot failure..." I am able to make it boot properly by inserting my emergency start up floppy and on the A: \> prompt typing FDISK /MBR. then all is OK for a few days then the problem comes back.

    Would it help to also type SYS C: at the prompt?

    One tip I read said to type "C:" first, then the above two commands. What effect would this have?

    Why does typing FDISK /MBR on the A: \> prompt with the emergency S/U disk in fix the proplem, albeit temporarily?

    What else should I be doing? Would prefer nothing too drastic if possible, as it seems to me the problem can't be too bad since it can correect and reboot properly for a while.

    Any help would be most welcome!

  2. #2
    --:-- Murray P's Avatar
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    Default Re: "Disk boot failure" and FDISK /MBR Command

    Firstly, I'b be backing up all my important data to somewhere other than the drive in question. You may have a failing hard drive.

    Then check that the drive ribbon cables are all securely in place. Next run the drives diagnostic utility. If they have a utitlity that can differentiate between the IDE controller and the logic board on the drive and test the communication between them would be ideal (rather than just a surface scan of the disc).

    Follow the instructions for repairing/replacing the MBR for the system directory C:, not the A: floppy disc you have inserted.

  3. #3
    Senior Member pctek's Avatar
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    Default Re: "Disk boot failure" and FDISK /MBR Command

    Yes sounds like imminent HDD death is approaching.

  4. #4
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    Default Re: "Disk boot failure" and FDISK /MBR Command

    Quote Originally Posted by Murray P
    ...
    Follow the instructions for repairing/replacing the MBR for the system directory C:, not the A: floppy disc you have inserted.
    It has been fixing the hard disk's MBR. FDISK doesn't know about floppy drives.

    SYS C: just replaces the DOS boot (hidden) files and the COMMAND.COM (which is the DOS OS). If the "fixed" MBR boots OK they are all right.

    It seems a bit odd. It's unusual for just the first few sectors (or any) to become "temporarily" bad. I'm wondering whether the drive is just a bit too slow in getting up to speed. (Cold weather, drive getting a bit old and tired ...)

    Instead of booting a floppy when this happens, try just a Ctrl/Alt/Del reset. If I'm right about the drive being a slow starter, it will boot with no more nonsense. It will be up to speed by then.

    Of course it could be symptoms of a forthcoming bad failure.

  5. #5

    Default Re: "Disk boot failure" and FDISK /MBR Command

    Yes, it does seem to happen more when the computer has been off overnight or for a day or so. I read somewhere that older hard drives can develop a sort of film on them, which slows them down just long enough to miss the boot command initially?? I will try what you suggest meantime. A bit puzzling at present.

  6. #6
    Smiling Down On Youse SurferJoe46's Avatar
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    Default Re: "Disk boot failure" and FDISK /MBR Command

    check psu voltages at start too..sometime a component in it fails ever so slowly and lets the boot voltage drop too low with all the demand at start up.

    just a thought.......................
    The problem with going to the stars is only the first few hundred miles.

  7. #7

    Default Re: "Disk boot failure" and FDISK /MBR Command

    [QUOTE=SurferJoe46]check psu voltages at start too
    QUOTE]

    What's the easiest way to do that please?

  8. #8

    Default Re: "Disk boot failure" and FDISK /MBR Command

    Quote Originally Posted by SurferJoe46
    check psu voltages at start too..sometime a component in it fails ever so slowly and lets the boot voltage drop too low with all the demand at start up.

    just a thought.......................

    Thanks. This could be valid comment, as PSU is only 250 watts. But how do I check the voltages?

  9. #9
    --:-- Murray P's Avatar
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    Default Re: "Disk boot failure" and FDISK /MBR Command

    Apart from a multi meter, I guess, most modern(ish) BIOSs will show your running voltages for various things. Sisoft Sandra may do the trick, but it does assume some things.

  10. #10
    Smiling Down On Youse SurferJoe46's Avatar
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    Default Re: "Disk boot failure" and FDISK /MBR Command

    The problem with using the bios monitor(s) that you may have is that you are gonna see the values once you are up and running...too late! It will not record or show the starting voltages.

    I suggest gently probing the 4-pin connex at the fans or the HDD wires and find the 12 VDC line while the unit is up/running, and then do a reboot and watch the voltages change.

    Try this also for the 5 VDC circuits...but I recommend NOT probing the 3.3 VDC areas at all, they will be a waste of time and they aren't that much affected by the other side of the PSU anyway..not that they MIGHT NOT be bad, but they are really for the MOBO anyway, and may not suffer as much.

    DO NOT use an analog VOM! The load that it creates is possibly gonna throw everything into the toilet anyway. Use of a Digital DVOM/DVM will not load the circuit you are testing and make a lot better guesstimate for what is happening.
    The problem with going to the stars is only the first few hundred miles.

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