If your computer has been hanging on a blue screen with CLASSPNP.SYS failed (error code: IRQL_NOT_LESS_EQUAL PAGE_FAULT_IN_NONPAGED_AREA etc.) while booting up, don’t worry. Below are 5 steps that have helped other users troubleshoot the problem. So read on and check them out…

5 steps to fix CLASSPNP.SYS 

All the steps below work both in Windows 10 and Windows 7.

Step 1 is more of a pre-step than an actual fix for you guys who CANNOT log in your Windows system.

Just work your way down from

  • Step 1 if you CAN’T log in your Windows 10/7;
  • Step 2 if you can log in your Windows 10/7.
  1. Enter Safe Mode with Networking
  2. Run SFC
  3. Update your device drivers
  4. Update your BIOS
  5. Check for hardware corruption

Step 1: Enter Safe Mode with Networking

I’m using Windows 10:

I’m using Windows 7:


I’m using Windows 10:

  1. Make sure your computer is off.
  2. Press the power button to turn on your PC. Then when Windows displays a login screen (i.e. Windows has fully booted), long press the power button to turn it off.

  3. Repeat 1) and 2) until the screen says Preparing Automatic Repair.
  4. Wait for Windows to finish diagnosing your PC, and click Advanced options.
  5.  Click Troubleshoot.  
  6. Click Advanced options.
  7. Click Startup settings.
  8. Click Restart.
  9. On your keyboard, press 5 to enable Safe Mode with Networking.
  10. Now you’ve successfully booted up in Safe Mode with Networking, continue with Step 2 to troubleshoot the blue screen problem.


I’m using Windows 7:

  1. Make sure your computer is off.
  2. Press the power button to turn on your PC and immediately press F8 at a 1-second interval.
  3. Press the arrow keys to navigate to Safe Mode with Networking and press Enter.
  4. Now you’ve successfully booted up in Safe Mode with Networking, continue with Step 2 to troubleshoot the CLASSPNP.SYS blue screen problem.

Step 2: Run SFC

System File Checker (SFC) is a handy feature in Windows that helps scan your system files and repair missing or corrupted .sys files that are causing our system the blue screen error. To run the SFC scan:

  1. On your keyboard, press the Windows logo key  and type cmd. Then right click on Command Prompt and click Run as administrator.

    Click Yes when prompted to confirm.
  2. In the command prompt window, type sfc /scannow and press Enter.It’ll take some time for the SFC to replace the corrupted system files with new ones if it detects any, so please be patient. 
  3. Restart your computer and see if the CLASSPNP.SYS blue screen of death issue has been solved.

Step 3: Update your device drivers

Nine times out of ten, this CLASSPNP.SYS  error occurs simply because you have the wrong/corrupted/outdated drivers on your computer. It can be difficult to put finger on which one is offending our system so you should update ALL the drivers available to resolve the situation.

If you don’t have the time, patience or computer skills to update your drivers manually, you can, instead, do it automatically with Driver EasyYou don’t need to know exactly what system your computer is running, you don’t need to risk downloading and installing the wrong driver, and you don’t need to worry about making a mistake when installing.

You can update your drivers automatically with either the FREE or  the Pro version of Driver Easy. But with the Pro version it takes just 2 clicks (and you get full support and a 30-day money back guarantee):

  1. Download and install Driver Easy.
  2. Run Driver Easy and click the Scan Now button. Driver Easy will then scan your computer and detect any problem drivers.  
  3.  You can upgrade to the Pro version and click Update All to automatically download and install the correct version of ALL the drivers that are missing or out of date on your system.

    You can also click Update to do it for free if you like, but it’s partly manual.

  4. Restart your computer hopefully the CLASSPNP.SYS blue screen issue has been fixed. If the problem persists, move on to Step 4, below.

Step 4: Update your BIOS

BIOS (Basic Input/Output System) performs the hardware initialization and jumpstarts the processes during the booting process of your computer. So we can try updating our BIOS to see if it sorts out our CLASSPNP.SYS  blue screen issue.

Important: Updating BIOS incorrectly might incur loss of data or even more serious problems. So please proceed with caution or seek professional help in the BIOS updating process.
  1. On your keyboard, press the Windows logo key and R at the same time, then copy & paste msinfo32 into the box and press Enter.

  2. In the information in BIOS Version/Date and go to the manufacturer’s official website.
  3. Check out the Support (or Download) section and search for the latest BIOS update.
  4. Download the file and install it properly. 
  5. Restart your PC and see if the CLASSPNP.SYS blue screen problem has been resolved. If yes, then great. But if it doesn’t work, don’t worry. There’s one more step for you to try.

Step 5: Check for hardware corruption

Your CLASSPNP.SYS blue screen problem can also happen because of a damaged hard drive. So we might have to run the built-in tool to scan our system for disk error and fix them if finds any.

The disk error scanning takes only a few minutes. But once it detects any errors, the fixing procedure can take HOURS to complete. Make sure you have enough time set aside.

To do so:

  1. On your keyboard, press the Windows logo key  and E at the same time, then click This PC.
  2. Right-click on Local Disk and click Properties.
  3. Click the Tools tab > Check.
  4. Click Scan drive.
  5. Follow the on-screen instructions for Windows to detect and fix the errors found.
  6. Restart your computer and see if the CLASSPNP.SYS error has been fixed.

If all else fails, then it’d most likely be hardware issues. Be sure to leave your computer with professional hands so as not to compromise your PC.


There you go – top 5 fixes for your CLASSPNP.SYS blue screen issue. Hope this helps and feel free to drop us a comment if you have any further ideas to share with us. 🙂

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