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Win7 won't boot...gets stuck at classpnp.sys in Safe mode

    Question

  • I recently tried partitioning my hard drive, but canceled it in G parted a little after I started it.  I then went to boot into 7 and it worked fine. After I restarted though, the win7 logo would come up, then my PC would restart.  In recovery mode, none of them will work, and when I try to boot into safe mode, it gets stuck at the classpnp.sys, then restarts.

    Any help?
    Sunday, August 30, 2009 2:58 PM

Answers

  • Reboot to the Win7 DVD and run the repair function. It may take some time to run but hopefully will correct the problem.


    • Proposed as answer by Robinson Zhang Tuesday, September 01, 2009 2:20 AM
    • Marked as answer by Novak Wu Monday, September 07, 2009 1:26 AM
    Sunday, August 30, 2009 4:10 PM

All replies

  • Reboot to the Win7 DVD and run the repair function. It may take some time to run but hopefully will correct the problem.


    • Proposed as answer by Robinson Zhang Tuesday, September 01, 2009 2:20 AM
    • Marked as answer by Novak Wu Monday, September 07, 2009 1:26 AM
    Sunday, August 30, 2009 4:10 PM
  • Same issue here. Windows 7 reboots but stops at classpnp.sys and restarts.
    Repair function did not help so fare...
    Cheers Harry
    Friday, September 18, 2009 1:23 PM
  • I have the same problem. I couldn't even install.

    I booted up with dvd and repair, however it didn't work.


    Is this a problem with my graphic card?

    I am using ati HD2400
    Monday, October 26, 2009 2:00 AM
  • I have the same problem, anybody can help?
    Wednesday, November 04, 2009 9:59 AM
  • I have a similar problem. Please help! Win7 boots until the glowing logo and 'starting windows' screeen appears. HDD is busy for about 30 secs and then just stops for about 2 minutes 15 seconds and then bootup continues. No problems after that.

    I did have XP before and never experienced this problem. I have tried repair options with the win7 dvd as well as doing a fresh install and the problem still persists. Other forums have suggested:

    1) Updating BIOS to the latest ... no help
    2) Disabling ACPI/APIC in the bios ... no help. PC refuses to boot after disabling this.
    3) Changing Plug n Play OS from No to Yes in bios ... no help
    4) Disabling Lan Boot in bios ... no help. Was already disabled.
    5) Removing USB and Lan cables connected to PC ... no help

    This is a fresh install of Win7 Ulitimate x64 with only Office 2007, Bitdefender Total Security 2010 and Acrobat Reader 9.2 installed.

    Pc config is:
    Asus P5Q mobo
    Intel Q6600 quad core CPU
    Geforce 8800GT graphics card
    4gb (4 * 1Gb) OCZ DDR800mhz Ram
    1 * Seagate 250Gb (boot drive) 1 * Seagate 500Gb HDD, 1 * WD 250Gb HDD, 1 * Seagate 500Gb. All of them SATA II.

    I feel it must be related to CLASSPNP.SYS. Any help will be apprecaited.
    Monday, November 16, 2009 12:45 PM
  • I just got it to work, though I don't understand why did it work.

    I just remove all pci card  including my graphic card, which I guess was the problem.

    The installation went fine.

    Then I could download a driver for my graphic card and everthing is good.

    Monday, November 16, 2009 10:21 PM
  • I have a similar problem. Please help! Win7 boots until the glowing logo and 'starting windows' screeen appears. HDD is busy for about 30 secs and then just stops for about 2 minutes 15 seconds and then bootup continues. No problems after that.

    I did have XP before and never experienced this problem. I have tried repair options with the win7 dvd as well as doing a fresh install and the problem still persists. Other forums have suggested:

    1) Updating BIOS to the latest ... no help
    2) Disabling ACPI/APIC in the bios ... no help. PC refuses to boot after disabling this.
    3) Changing Plug n Play OS from No to Yes in bios ... no help
    4) Disabling Lan Boot in bios ... no help. Was already disabled.
    5) Removing USB and Lan cables connected to PC ... no help

    This is a fresh install of Win7 Ulitimate x64 with only Office 2007, Bitdefender Total Security 2010 and Acrobat Reader 9.2 installed.

    Pc config is:
    Asus P5Q mobo
    Intel Q6600 quad core CPU
    Geforce 8800GT graphics card
    4gb (4 * 1Gb) OCZ DDR800mhz Ram
    1 * Seagate 250Gb (boot drive) 1 * Seagate 500Gb HDD, 1 * WD 250Gb HDD, 1 * Seagate 500Gb. All of them SATA II.

    I feel it must be related to CLASSPNP.SYS. Any help will be apprecaited.
    Acer 1410, same symptoms experienced Win7 Home Premium immediately upon clean boot (formatted drive, clean install).  Stalls for about 2 minutes every boot at classpnp.sys, then eventually resumes.  Seems like a timeout to me, something waiting to for a response or trigger it never sees.

    Very frustrating!

    I sure love Linux.  Stuff like this is rare, and if it does happen, the hood is not welded shut, I can poke around and find the root cause and fix it, definitively.

    Have done ALL the updates, incl. drivers, no joy.

    Oh, and I DID follow recommendations I found on this subject posted elsewhere, no joy.  Repair from disk, safe mode, etc.
    • Proposed as answer by SRV69 Sunday, June 06, 2010 6:26 AM
    Monday, January 11, 2010 4:10 PM
  • FIXED IT !!!!

    I tried all of the fixes mentioned from replacing the classpnp.sys file to others.  I dual boot so I had a chance to reinstall windows 7 but that isn't the fix.

     

    Go into your bios and check the hard drive configuration.   Once I reverted back to IDE the system booted as normal.  You may have to do the opposite!!!

     

    At all times my system hung at classpnp.sys as advertised.  Let me know if this fixed

     

    • Proposed as answer by SRV69 Sunday, June 06, 2010 6:27 AM
    Sunday, June 06, 2010 6:27 AM
  • FIXED IT !!!!

    I tried all of the fixes mentioned from replacing the classpnp.sys file to others.  I dual boot so I had a chance to reinstall windows 7 but that isn't the fix.

     

    Go into your bios and check the hard drive configuration.   Once I reverted back to IDE the system booted as normal.  You may have to do the opposite!!!

     

    At all times my system hung at classpnp.sys as advertised.  Let me know if this fixed

     

    This is probably a good suggestion.

    Today, when I've opened my desktop, it was so dirty and I just couldn't even find board controllers.

    I'm gonna clean everything tomorrow and see if this hint helps! TkS!

    Thursday, July 01, 2010 2:54 AM
  • Many thanks! It worked for me! But now my hard drive is running in ATA mode, not AHCI.

    Tuesday, August 31, 2010 5:56 PM
  • Hi all, just thought I'd post about my solution to this problem as well.  I was streaming video online, my pc restarted and I got the STOP: 0x7B error.  I would hang on the classpnp.sys in safe mode as well and then my pc would reboot itself.  Ran repair from DVD and tried just about everything I could think of.  Then After exhaustive searches for help, I came across this thread, went into my BIOS and switched from Sata IDE to AHCI, and voila! it started right up!  So have hope, if you try hard enough you can find a solution to your issue.

    Specs:  Windows 7 Home 64bit, ATi HD5770, Asus p7h55d-m Evo mobo, 2 gb ram, onboard sound

     

    Tuesday, October 05, 2010 2:25 AM
  • SRV69 I could kiss you.   This issuse has been plaguing me for over a week, but thanks to a newborn, and a milion other more important things I couldn't dedicate the time to getting this fixed until this morning (I still probably have spent 4-5hrs trying to get this to work).  I wonder what client I can bill this time to.  :)

    THANK YOU!

    Tuesday, November 22, 2011 3:57 PM
  • Tried  everything on here, ide, ahci, and raid, still hangs on that damned classpnp.sys :(
    Friday, November 25, 2011 1:04 AM
  • I had this issue with Windows Server 2008 R2 and an Asus board.  I found that the board had both a Marvell controller and the Intel controller for 6Gbit SATA (I have no idea why).  Plugging the HDD into the Intel controller instead of the Marvell one fixed the problem.  I doubt there is anything really wrong with the Marvell controller -- it was probably a driver issue, but I really don't care what controller the OS disk uses so I didn't troubleshoot further.
    Tuesday, April 10, 2012 10:15 PM
  • Thanks so much. Your solution worked for me :)

    Friday, June 08, 2012 1:01 PM
  • i lovff you man!!! i totally forgot that i set the bios to compatibility trying to install ubuntu. then i couldnt get back into windows with the bsod. lord knows i wont remember this next time it happens, but its good to know someone has a better memory than i do
    Thursday, June 14, 2012 11:44 PM
  • This means there is a hardware problem on the pc. In my case I was running a HP with built in tests for HDD and Memory in BIOS. It passed Mem test but failed HDD.

    My HDD had bad sectors. I pulled out my HDD and used a SATA to USB connector to connect it to another pc and used testdisk to recover all my lost data. Note when you connect it to another pc it will not be able to read the volume and prompt to format. DO NOT FORMAT. Testdisk will still be able to read this volume. You can download testdisk from the link below

    http://www.cgsecurity.org/wiki/TestDisk_Download

    Now that I had my data back I am running chkdsk from DOS to try and see if I can fix my broken HDD. Refer to:

    http://support.microsoft.com/kb/315265

    In my case from a XP machine I used chkdsk h:/f    (h: being my broken volume)

    In some cases it could be a faulty RAM in which case you will need to swap RAM's with a working machine or if you have more that one in your pc you can try testing them one at a time to see if it works. I have read success with pulling out CMOS battery but in my case with a bad HDD this would have been futile.

    Hope this helps!

    • Proposed as answer by debuk Wednesday, December 05, 2012 10:26 AM
    Monday, August 27, 2012 6:22 PM
  • Yep same issue after bios-updating my ASUS E-35M1-I deluxe mobo to v1404.  First of all AVG antivirus drivers gave me BSOD in Win7 (safe mode no help given how early the antivirus stuff loads in the process) so I booted Win7 cd and got into the c: and disabled those.  Then I get to this problem.  Followed your advice - and noted that the bios update had reverted my setting for disks to IDE when I built the machine as AHCI.  Flipped it back to AHCI.  Problem fixed and potential windows reinstall averted. Thank you.
    Saturday, December 08, 2012 5:22 PM
  • Same problem, hangs on classpnp.sys, then restarts.  My MB was set to Native IDE.  I tried ACHI, but the disk had a different problem, maybe because I have bitlocker enabled.  I tried some other settings and the "IDE -> ACHI" setting worked.

    Thank you!!!

    Sunday, May 05, 2013 1:43 AM