Laptop hangs up at Classpnp.sys file.

Anonymous
2009-10-30T12:33:24+00:00

So I installed Windows 7 the other night on my laptop.  I did the driver updates and installed Norton.  I also installed Office 2007.  Then I shut it down for the night.  The next day I turned it back on to install a few more things.  A friend recommended that I install Ad-Aware, so I did, and ran it.  I've used it on a few of my machines before with no problems.  I installed a couple more programs (SANDRA & CPU-ID) then I shut it down for the night.  It stalled on shutdown.  I didn't think anything about it and after about 20 minutes I did the power-off.  I started it up the next day and it now hangs at the starting windows screen.  I've tried the following with all the same results:

  • System repair - hangs at the repair screen
  • Start normally - hangs at the starting windows screen
  • Start in safe mode - hangs at the classpnp.sys file
  • Start in safe mode with command prompt - hangs at the classpnp.sys file
  • start in safe mode with networking - hangs at the classpnp.sys file

I've even tried to put in the windows 7 disc back in to do a re-install and it hangs at the starting windows screen.

It seems like no matter what I try I get the hang up at the windows starting screen.

Someone help, please!!!

Windows for home | Previous Windows versions | Windows update

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Anonymous
2009-11-08T15:10:27+00:00

So the other night I tried a few more things with all the same results.  Here's what I tried:

  • I bought a second gig of ram, so I tried swopping out one stick, then the other - same results.
  • I bought a hard drive enclosure, removed the hard drive, formatted it with another computer, made sure I could save things to it, re-installed hard drive, booted from CD - same results.
  • I bought a brand new hard drive, installed it, booted from CD - same results.
  • Put old hard drive back in with both sticks of ram - same results.

After reviewing a few things, I found that when Windows gets to the "Starting Windows" screen, it's checking your hardware to make sure that things are OK.  Well, my hard drive, RAM, CD Drive, and Video Card are OK (I get all the right video stuff), so there's only a couple of things left, and one is the motherboard.  So, I believe that there is a hardware issue that is not allowing Win7 to completely load.

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Anonymous
2010-12-13T17:26:25+00:00

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

Macbionik.com

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  1. Anonymous
    2011-11-01T16:29:10+00:00

    I have seen this problem on several different Win7 installations. I know that the most common response is to blame this on hardware (bad drive), but I don't buy this. My belief is that more often than not it is related to the BIOS - some sort of incompatibility between the BIOS and the OS. I cannot guarantee that this will fix the problem, but on my Dell Latitude running Win7 64-bit I was able to get past this 'ClassPNP.sys' hang by hitting F12 on startup, going into the BIOS and changing the SATA setting from RAID to  AHCI. I realize for those who need RAID this is not an option, but on a laptop that will never have more than 1 drive RAID is not necessary.

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  2. Anonymous
    2011-11-05T13:31:22+00:00

    I had the exact same problem, I was able to solve this by restoring the default settings on my BIOS.

    Once it worked, I compared my old BIOS settings, and my default one, the only difference was an incorrect HD on the HDD Group Boot Priority, somehow it got set by default my secondary HD instead of my primary.

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  3. Anonymous
    2011-11-11T16:06:24+00:00

    I had the same problem (laptop hang on boot at classpnp.sys) and solved it by removing power cord and battery, and rebooting with battery, hope this helps

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