Windows 7 PC Won't Boot - Stops At ClassPNP.sys


  1. Posts : 13
    Windows 7 Professional x64
       #1

    Windows 7 PC Won't Boot - Stops At ClassPNP.sys


    I've ended up with a PC that refuses to boot - gets as far as the "Starting Windows" screen, waits for a while and reboots - repeatedly.

    Starting in Safe Mode, it gets as far as ClassPNP.sys before stopping (for some time) and rebooting.

    I've tried:
    • Startup Repair - fails with an error that what looks like (and what I can remember), "O/S does not match".
    • I do not possess the installation DVD.
    • The BIOS does not have the option to switch between IDE, ACHI, Auto, etc. The BIOS has been 'factory reset'.
    • I've run CHKDSK more than once, with auto-repair (and some other option, can't remember which).
    • I've run SFC with the (what I can remember as) the C:\ and C:\Windows specified, several times, each time it ends with "I've tried to fix it, but I can't". So I got the CBS.Log onto another machine, ran the command that extracts the "SR" entries into another file. When I examined that file, all of the entries looked "OK" (no errors). All of the errors I could find were to do with Windows Updates (and 'TrustedInstaller' giving up).
    • "SeaTools" does not report the drive as defective.
    I've attached the CBS.Log, here.

    What else can I check? Can anyone help, please?
      My Computer


  2. Posts : 4,752
    Windows 7 Home Premium 32-Bit - Build 7600 SP1
       #2

    I had one like that and the HDD was gone. I hope you have backups because that is what it sounds like.
      My Computer


  3. Posts : 13,576
    Windows 10 Pro x64
       #3

    Create a system repair disc or install dvd (from another PC) and try a system restore from boot.
      My Computer


  4. Posts : 13
    Windows 7 Professional x64
    Thread Starter
       #4

    Thanks for the replies, but neither SeaTools (Seagate Drive Tool) or CrystalDiskMark report the drive as defective (certainly no more defective than the machine I am typing this on).
      My Computer


  5. Posts : 13
    Windows 7 Professional x64
    Thread Starter
       #5

    AddRAM said:
    Create a system repair disc or install DVD (from another PC) and try a System Restore from boot.
    I managed to find and build a bootable Win7 ISO on a USB stick - it would only perform a 'Clean Install', not a 'Repair Install'. There are no backups of this machine (it's not mine). The repair options gave me the same messages as before.
      My Computer


  6. Posts : 4,752
    Windows 7 Home Premium 32-Bit - Build 7600 SP1
       #6

    r44712 said:
    AddRAM said:
    Create a system repair disc or install DVD (from another PC) and try a System Restore from boot.
    I managed to find and build a bootable Win7 ISO on a USB stick - it would only perform a 'Clean Install', not a 'Repair Install'. There are no backups of this machine (it's not mine). The repair options gave me the same messages as before.
    If you have no backups or a disk for Repair Install, it sounds as if your options are limited. I would hope the Product Key is on a sticker on the PC so that you can do a Clean Install Windows 7
      My Computer


 

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