Laptop hangs up at Classpnp.sys file.

Anonymous

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!!!

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Anonymous

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

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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135 additional answers

Anonymous

2012-05-16T07:13:51+00:00
I know this is an old threat but I recently ran into it too and fixed it. Since this thread still shows up in search results, here's what I did to fix the boot record:
1. Boot using the Windows 7 install CD.
2. On the first screen you see, click "Next."
3. In the lower left of the next screen, click "Repair your computer."
4. Then choose "Command Prompt."
5. Type exactly: Bootrec.exe /FixMbr then hit "Enter." You'll see "Operation completed successfully."
6. Reboot the computer. If all goes well it should work.
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Anonymous

2012-04-26T14:52:48+00:00

No, it does not solve anything as some stated.

Go to for example bitsnoop.com and do a search for "windows 7 MSDN" all download the iso that contains only the original microsoft files and isntall it.

Then you will not see the boot hang on CLASSPNP.SYS
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Anonymous

2012-04-01T16:34:22+00:00

I have the same problem but am not finding this setting. I can change AHCI to IDE but that still doesn't solve the problem.
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