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Windows 7: Another classpnp.sys hangup

24 Mar 2010   #1

Windows 7 RC
Another classpnp.sys hangup

Same story. Machine, in this case a Dell Inspiron 32 bit, suddenly refuses to boot. I can get as far as the login, hit a profile and the welcome screen hangs. Try to boot in safe mode and it sticks on classpnp.sys.

I've scoured this and other forums for a solution and found only two. Reformat and reinstall, whic I can't do because it is an upgrade disc from Vista. And replace the classpnp.sys file. I was wondering if anyone would be willing to walk me thru the process? I don't have a lot of knowledge about working with the command prompt. I've got a copy of Ultimate Boot CD if that is of any assistance.

My System SpecsSystem Spec
24 Mar 2010   #2
Bare Foot Kid
Microsoft MVP

W 7 64-bit Ultimate

Hello Dedalus2k.

Have a look at the tutorials at the links below; you can do a clean install with an upgrade disk; be sure to post back with an update.

Clean Install with a Upgrade Windows 7 Version

Clean Install From Upgrade Vista - Vista Forums
My System SpecsSystem Spec
24 Mar 2010   #3

Windows 7 x64

Do you have any idea what might have disturbed your install? Do you remember getting an Windows update message?

The postings I have found seem to indicate replacing the file might help. How can you do that, possibly one of three ways.

If you can boot to the Install DVD, go to the command prompt and run SFC /scannow. Maybe it will find and fix it.

You could also replace the file yourself from within the command prompt. Someone here could probably send you a 32 bit version.

Someone else used a live Ubuntu CD to start Linux on their system and use it to replace the file. A live CD does not install, just runs from memory.

Also, even though I have not done it, if you knew for sure if it was a Windows update you might be able to uninstall it using pkgmgr.exe from that same command prompt.

Another thing, which I saw was tried and did not work, would be to set the bios from PnP OS installed to the other option, yes or no.

Is there anything you can unplug, or turn off in the bios? It is checking some device and causing problems.

My best guess is you got an optional hardware driver from Microsoft and it has messed up your system, unless you have another suspect.

I remember a tutorial somewhere that talks about starting Device Manager in an emergency situation, I will try to find that.
My System SpecsSystem Spec

25 Mar 2010   #4

Windows 7 RC

Thanks for the input y'all. I ran chkdsk /r on the drive and it found and repaired 5 bad sectors. classpnp.sys I imagine was on one of them. It didn't help any however. Took your advice Bare Foot Kid and did a clean install with my Win 7 Home Premium upgrade disc and viola, no problems. And as an added bonus no more damned Dell bloatware. Installed Diskeeper on it too. Somehow I neglected to previously.

Thanks Again!
My System SpecsSystem Spec
25 Mar 2010   #5
Bare Foot Kid
Microsoft MVP

W 7 64-bit Ultimate

Hello again Dedalus2k, you're welcome!

Real glad you found a solution, thanks for the update!

Here's a really useful tutorial you may want to have a look at, at the link below.

System Restore Point : Create at System Startup
My System SpecsSystem Spec
23 Aug 2011   #6

Not a solution

Love that my post is 516 days after the last and still no solution is shown.
So How do you come to believe that re installing is a solution? To the majority of end users, they cannot boot up to save files. Then to delete there entire hard disk and re install is a failure. Not a solution.

I am seeking also a solution to this. I thought about trying the bootsuite 2011 , and not sure if i should now. Yes its a 2011 verison, but the guy in this thread stated he or she also had this disc in their possession and was seeking a solution to this problem....
My System SpecsSystem Spec
12 Oct 2011   #7

windows 7 ultimate x64
Reset bios

I had a classpnp.sys hangup that was fixed by simply resetting the bios the oldschool way. (removing the battery for 30sek). The problem started after a win7 update but I didnīt bother to find out what the exact problem was.
My System SpecsSystem Spec
07 Aug 2012   #8

Windows 7 Home Premium 64bit

I did EXACTLY what the last poster suggested & it worked. I could not do anything else. Recovery dvd did not work, safe mode refused to work..... I was ready to throw out a brand new laptop.

Then I unplugged, turned off & took the battery out. Waited 30 seconds...then put it back in. BAM it all loaded no problem. I was then able to do a repair & not a problem now.

I'd like to know how this problem happened in the 1st place. Son only installed winrar, then Thunderbird & turned the laptop off. When he went to turn it back on an hour later there was the problem. I've now shown him how to solve the problem should it arise again.

So why did it happen? How did it happen? What are the chances of it happening again?
My System SpecsSystem Spec

 Another classpnp.sys hangup

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