Windows 10: The operating system does not start

After my son changed something in the BIOS, the computer says when booting: Reboot and select proper boot device. I checked that all storages are connected and the system boot priority is correct. I tried resetting the BIOS settings but it didn't help. I think that I need to install Windows again, but I didn’t find the key for it on the computer case, there is just a Windows sticker and the model and series of my computer Cyberpower, could you help me with activating a new Windows or restoring the previous one

:)

 

' choose an operation system to start"

Hi Bob,

To better assist you, do let us the complete message that you receive.

Sometimes, this could be due to two operating system installed in your computer. Just to make sure this is not the case, I suggest you to try the steps below:

1. Press Windows key + R.

2. Type msconfig and press enter.

3. Click the "boot" tab and check if there are any other operating system listed.

4. In addition, change the timeout time to 3 seconds(default)

Let us know the result, we will be glad to help if you need further assistance.

 

Programs not working

In post 26 there were steps listed to fix the operating system corruption.
Are you able to follow them?
In post 29 was the suggested dism repair command.

 

Error: "An operating system wasn't found. Try disconnecting any drives that don't contain an operating system"

Hi Stephen,

I realize the inconvenience you are facing in accessing the operating system. Now that you have me with you let me take care of this.

Do let us know if you are able to see Windows 7/ Windows 10 operating system while rebooting the device?

As you are unable to boot the operating system, this issue might have occurred when the boot files are missing or corrupted.

I suggest you re-built the boot rec by following the below commands and check if it helps.
You will have to use Windows 10/7 installation media to follow the steps to boot into Recovery Environment and try to rebuild BCD.

Step 1: I suggest you to create an installation media for
operating system using the media creation tool

If system boots to Windows 10:
Installing Windows 10 using the media creation tool

If system boots to Windows 7: Download Windows 7 Disc Images (ISO Files)

Step 2: After preparing the installation media, insert it hard reboot the device and follow the below:

• Boot into Windows Recovery Environment using the Windows 10/7 installation media.
• Click on Repair your computer.
  
• Click on Troubleshoot and in the Advanced options.
• Select Command Prompt. Type the following commands into the prompt and press Enter key after each command.

• bootrec /fixmbr

• 
  bootrec /fixboot
  
• 
  bootrec /scanos
  
• 
  bootrec /rebuildbcd
  

5. Restart the computer.

NOTE: Modifying BIOS/ complementary metal oxide semiconductor (CMOS) settings incorrectly can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting
from the configuring of BIOS/CMOS settings can be solved. Modifications of the settings are at your own risk.

Hope it helps. Reply to the post with an updated status of booting the operating system for further assistance.

Thank you.