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8 April 2024  Jennifer Thatcher  Technology Manager of Test Dept.
 

Summary
Discover the underlying causes and standard solutions for the "Operating System Not Found" error on Windows PCs. We'll also cover how to safeguard your data by transferring it during the troubleshooting process.



Table of contents

table iconI. Reasons for the error No operating system found when starting Windows
table iconII. Use Renee PassNow to transfer or recover important data before repairing
table iconIII. How to Fix Operating System Not Found Error on Windows?
operating system not found

I. Reasons for the error No operating system found when starting Windows

Various errors can occur in Windows, but the “operating system not found” error indicates a significant computer failure. Common causes include:
●The BIOS configuration is incorrect.
●The power cord is damaged or the cable is connected incorrectly.
●The hard disk drive is frozen or damaged.
●The subsequent files of the boot file are damaged, and the operating system cannot be fully loaded. You can try to repair the boot file through the Bootrec command.
To prevent data loss, back up critical data using professional system rescue tools before addressing the issue. If data transfer is unnecessary, proceed directly to the repair instructions in part three.

II. Use Renee PassNow to transfer or recover important data before repairing

1. What is Renee PassNow?

Renee PassNow is a versatile system rescue software designed for Windows users. It offers a suite of tools to reset Windows account passwords, create new administrator accounts, recover data from disks or memory cards, and transfer files between disks. Additionally, it can erase or scan disk files and repair common Windows system issues, such as MBR boot record, DBR error parameters, 0xc00000e boot errors, startup failures, and blue or black screen problems. Compatible with Windows 10/8.1/8/7/XP/Vista, Renee PassNow caters to diverse system rescue needs.
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Highly compatible Windows 10/8.1/8/7/XP/Vista. Also supports UEFI boot mode.

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2. How to use Renee PassNow to transfer or recover data?

If your computer fails to boot, create a startup disk using Renee PassNow. Boot the computer from this disk and utilize the software’s data transfer and recovery features to operate. Follow the specific steps provided.
Step 1: Install Renee PassNow on a functioning computer. Connect a USB drive to the PC and launch Renee PassNow. Select Step 1: Select creation method and choose the Create a rescue USB disk option. Ensure that you back up any important files from the USB drive to another location before proceeding, as this process will erase all data on the USB drive.
Step 2: Next, select (x64) or (x86) according to the system type, click the (Download Now) button to download the ISO file, click the (Create Rescue USB) button after the file is downloaded, and click the (Eject USB) button.
use renee passnow to create usb to reset passnword
Step 3: With the boot device prepared, insert it into the target computer. Switch on the computer and be on the lookout for the BIOS shortcut key prompt that flashes on-screen for a brief moment—typically only 1-2 seconds. Press the BIOS key repeatedly to enter the BIOS settings. In the BIOS menu, proceed to the Boot Priority options and designate the USB drive as the first boot choice. Remember to save these changes and restart the computer.
select boot order
Step 4: After the Renee PassNow software has loaded, select Data Transfer to migrate particular files. If you need to clone the entire hard disk, opt for the Data Backup feature to copy all data to a different drive.
data transfer
Step 5: Click on each disk drive letter to check for any missing important files. If all files are accounted for, transfer them to an external disk for safety. To transfer data, select the source drive (e.g., C drive), then the destination drive (e.g., G drive), choose the files you wish to copy, and click the ‘Copy’ function button. To delete a file, select it and hit the ‘Delete’ button, but remember that this action is irreversible, so proceed with caution.
transfer data interface
Step 6: If you find that there is data loss, please select the (Undeleter) option on the main interface of the function, and click the (Run) button.
Data recovery function of Renee Passnow
Step 7: Select (Whole Disk Scan) to scan the target hard disk.
Step 8: After the scan completes, select the desired file for restoration and press the Recover button to start the data recovery procedure. Ensure to save the restored file onto an alternate external disk. Post-recovery, perform a safe ejection of the USB drive before proceeding with any computer repairs.
preview before recovery undeleter preview docx
The above are the detailed steps to transfer or restore data, let’s learn how to fix the “operating system not found” error on Windows.

III. How to Fix Operating System Not Found Error on Windows?

1. Check the BIOS startup sequence

If you encounter the “No operating system found” error, it may be due to an incorrect BIOS boot sequence where the system disk is not set as the primary boot device. To resolve this, ensure the BIOS recognizes the system hard disk and verify the boot sequence settings. Follow these steps:

Step 1: Press the power button on your computer, then immediately tap the appropriate shortcut key (commonly F2, F10, Esc, or Del) to access the BIOS. The key will typically be displayed at the bottom of the screen during startup.
Power on and click the button to enter the bios settings
Step 2: Navigate to the Boot Priority setting in your BIOS. The terminology might differ—search for terms like “Priority” or “Boot Order”. Select the hard drive containing the Windows OS and designate it as the primary boot device. Save the modifications by pressing F10 and confirm the changes. Finally, restart your computer.
Detection related options

2. Detect hard disk problems

If your hard disk fails and you encounter the “no operating system found” error, access the BIOS to diagnose the issue using your motherboard’s built-in hard disk detection utility. Detailed instructions are available on the motherboard manufacturer’s official website. Follow the provided steps for troubleshooting.
Step 1: Continuously click the shortcut key to enter the BIOS during the boot process to enter the BIOS.
Step 2: Utilize the arrow keys to navigate to the “Diagnostics” or “Hard Drive Self Test” option. Select it and press Enter to initiate the hard drive detection process. Should any damage be detected, it is imperative to solicit professional repair services. Conversely, if the hard drive remains unscathed yet the operating system cannot be located, continue with additional troubleshooting procedures.
Detect hard disk

3. Modify the BIOS to default settings

When the BIOS setting is wrong, it will also cause your computer to appear the error of “no operating system found”. In this case, you only need to modify the BIOS to the default setting to solve it. The specific operation steps are as follows:
Step 1: Continuously click the shortcut key to enter the BIOS during the boot process to enter the BIOS.
Step 2: Save the BIOS settings, and then restart the computer to check whether the operating system starts normally.
load defaults
For additional Windows startup solutions, visit the Microsoft official guidance page. Note that this content is tailored for professional technicians; if you’re unfamiliar with the material, it’s advisable to consult with experts or contact the official support team rather than attempting to troubleshoot on your own.