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
    2016-02-01T12:21:46+00:00

    This worked for me. Thanks.

    Althought, I switched sata operation in Bios to ATA. It was selected to IRRT.

    Don't know what is was before, because I wasn't chanced anything in bios at anytime. Laptop was not used about 1 month and it was without battery that time, and when I start it again it did this boot loop wich stopped at classpnp.sys.

    Propably bios has reseted because battery was off and it has chanced sata to IRRT, don't know?

    Laptop is Dell Latitude E6400.

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  2. Anonymous
    2016-05-25T01:42:33+00:00

    I have been reading all the threads to try and fix this and was not looking foward to rebuilding PC but I got lucky. Suggest you try this for yourselves as it worked for me.

    • Reboot in Safe Mode with Command Prompt
    • When the boot script freezes at "CLASSPNP.SYS" line hit <ctrl><break>
    • When I tried this it killed the frozen command line session and then Windows went on to reboot in safe mode
    • I then restarted in normal mode and hey presto no more problems
    • Not yet anyway

    What a surprise that an old MSDOS keyboard command seems to be able, at last in my case, to fix what appears to be a significant Windows problem for so many...

    Makes you think

    Hope this saves a few people from having to do major reinstall work or hardware fixes

    Andrew, you are a GOD!  NOTHING was working for me.  I tried every other "fix" others posted to get past that CLASSPNP.SYS hangup.  Nothing worked and I could not get into safe mode--period.  

    Microsoft was NO help, huge surprise.  Dell, the manufacture of my laptop (a top of the line XPS running win7) were no help.

    Your <ctrl> <break> or in the case of my Dell, since they don't have <break> keys, dell keyboards emulate it by <cntl> <fn> <f12>.  Did that and BAM, safe mode booted up and I was able to pull everything off my harddrive onto a flash drive.  Once I confirmed this, I bought a Mac--because I'm **** done with PCs and Microsoft can kiss it--and once all my files were confirmed to be on my new mac, I literally took a sledge hammer and destroyed the dell which released the last amount of frustration I had prior to coming across your fix.

    I told my wife that if I ever meet you I'm going to kiss you on the mouth.  Or by you a beer, your choice. 

    THANK YOU!

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  3. Anonymous
    2016-05-25T12:56:48+00:00

    It likely does have to do with the BIOS. When my laptop isn't shut down properly, it hangs on boot as described by others (at CLASSPNP.SYS when booting in safe mode). What *always* works is unplugging the power supply and removing the battery for a few seconds. This must reset something deep down, and it boots normally afterwards.

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