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Windows 7: OS not loading, Safe Mode won't boot past classpnp.sys

18 Jul 2014   #1

Windows 7 64-bit SP1
OS not loading, Safe Mode won't boot past classpnp.sys

I replaced my Intel Q6600+DP35DP mobo with an i5-4690K and Asus Z97 K. I get a "missing operating system" message. When I boot up with a Windows 7 64 bit installation USB and then Repair Your Computer, it does find the OS on the hard drive still.

I tried following this guide for repairing the boot manager
How to Fix Windows 7 When It Fails to Boot

but I didn't get anywhere, until I tried this part
*Some users also find simply deleting the boot folder and retrying the above steps effective at resolving boot issues, but it is not recommended.
Now instead of "Missing Operating System" I get the "Windows Error Recovery. Windows failed to start. A recent hardware or software change might be the cause" then it recommends I do the startup with the installation disc and repair my computer.

If I instead Start Windows Normally, it displays a few seconds of the startup animation then auto restarts.

If I chose Safe Mode, it shows Loading Windows Files until it gets to windows\system32\drivers\classpnp.sys, pauses for a second then restarts.

If I boot up with the installation USB again, and selecting my Windows installation it will tell me "You computer was unable to start; StartUp Repair is checking you system for problems" and start searching for problems for a few minutes, and then attempting repairs for a few minutes, and then it will give me "startup repair cannot repair this computer automatically"

And then it has these details.
Event Name: StartupRepairOffline
OS Version: 6.1.7601.
Locale ID: 1033
After that if I try to repair startup from the next screen it will give me "startup repair could not detect a problem" *shrug*

I've tried both SFC and DSKCHK but neither of them have reported any problems.

My System SpecsSystem Spec
18 Jul 2014   #2

Windows 7 ultimate 64-bit

Well if im not mistaken; anytime you switch to a new motherboard; it is generally a good idea to do a completely fresh install of the windows operating system because the drivers for the motherboard will be different etc. But also; before doing a fresh install of windows; try following the steps in the following link and see if that doesnt help ya out. If not; post back and we can go from there.

Troubleshooting Windows 7 Failure to Boot
My System SpecsSystem Spec
18 Jul 2014   #3

Windows 7 Home Premium 32-Bit - Build 7600 SP1

I agree with Matts6887 that a Clean Install Windows 7 is needed to get things going for you. You will need the Product Key to activate the Win 7 after it is installed. Since you have a Custom Build, I assume you have a Win 7 disk from your first installation. The Product Key will be on the DVD. == If your Win 7 DVD is a OEM copy, you are not allowed to use it again when a motherboard has been changed. OEM copies are tied to the motherboard and are not transferable. A new copy will have to be purchased.
My System SpecsSystem Spec


 OS not loading, Safe Mode won't boot past classpnp.sys

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