my desktop wont start up (boot device not found) how do i install new OS?

Question

did not install os update, now desktop will not boot

Answer 1

Welcome Ed Hamilton,

Thank you for reaching out to Microsoft Q&A forum.  

I understand that your desktop does not start and shows a Boot device not found message 

To speed up the resolution, please confirm the following:  

• Did this issue start after a recent Windows update, power outage, or hardware change? 
• Are you able to access BIOS/UEFI and see your internal drive listed there? 

Besides the earlier recommendations, you may find these additional options helpful:  

Option 1: Check BIOS/UEFI boot detection 

• Restart the PC and enter BIOS/UEFI using the manufacturer key (such as F2, F10, Del, or Esc) 
• Confirm that the internal HDD or SSD is detected 
• Make sure the drive is set as the first boot device 

Option 2: Use Windows Automatic Repair 

• Power on and interrupt startup twice to enter Automatic Repair 
• Select Advanced options 
• Choose Startup Repair and allow it to complete 

Option 3: Check the disk using Command Prompt 

• From Advanced options, open Command Prompt 
• Run the disk check on the Windows drive using the appropriate drive letter 
• Restart the device after the scan completes 

I really hope that the information I gave above was helpful to you. Please feel free to reply below and let me know if you have further concern on this matter.    

---

PS: If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".     

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

Answer 2

If your desktop is showing a "boot device not found" error and you need to install a new operating system, you can follow these steps:

1. Create Installation Media: You will need a USB drive or DVD with the Windows installation files. You can create this using the Windows Media Creation Tool from another working computer.
2. Boot from Installation Media: Insert the installation media into your desktop. Restart the computer and enter the boot menu (usually by pressing a key like F12, F2, or ESC during startup). Select the USB drive or DVD as the boot device.
3. Install Windows: Once you boot from the installation media, follow the on-screen instructions to install Windows. You may need to format your hard drive during this process, which will erase all data on it.
4. Reboot: After the installation is complete, remove the installation media and reboot your computer.

If you encounter any issues during the installation, such as missing drivers, you may need to ensure that the necessary drivers for your hard drive are included in the installation media or provided during the setup process.

---

References:

• Install a boot-start driver
• Advanced troubleshooting for Stop error 7B or Inaccessible_Boot_Device