Is Windows not booting up on your computer? Are you seeing the error message “An operating system wasn’t found” on a blue screen? If this is happening then there is a problem that involves the wrong partition of your HDD to be identified as the boot drive of your system. Don’t worry. Follow these easy fixes and the problem will be solved in no time at all.
Pre-requisite–
You will need a Windows installation media. If you don’t have one, you have to create a bootable installation media.
Once you have done so you can go ahead to the main solutions.
Fix-1 Activate the boot drive-
As we have said before, this problem may occur due to the wrong boot drive configuration.
1. At first, insert the installation media you have created (or the Windows 10 installation DVD) on your computer.
2. Press any key from your keyboard to boot from the DVD.
3. Now, set your language preferences and click on “Next“.
4. Now, click on “Repair your computer“.
5. When the Troubleshooting window pops up, click on “Advanced options” to see advanced options on your screen.
6. When the Advanced options window, click on the “Command Prompt” to access it.
7. In Command Prompt window, copy-paste these two commands one-by-one and hit Enter to execute both of the commands sequentially on your computer.
diskpart list disk
9. To select the particular disk where Windows is installed on your computer, execute these codes.
select disk <your disk no.>
list vol
[NOTE– Replace the “<your disk no.>” with the particular digit which signifies the HDD drive where the Windows is installed.
For this computer, it is “Disk 0“. So the command will be like this-
select disk 0]
10. To select the System reserved volume you need to execute this particular line.
select vol <volume no.>
[NOTE– Replace the “<volume no.>” which is declared as “System reserved” in the list of volumes. If you don’t see ‘System Reserved‘ in the list of volumes, it is the drive where Windows is installed.
Example- For us, it is “C:” drive where Windows is installed, so it is ‘Volume 2′. So the command will be –
select vol 2
11. Now, you have to assign a new drive letter to the partition(You can enter any letter from “M” to “Z“.). Copy-paste this command in Command Prompt window and hit Enter to do so.
assign letter=V:
When you see that there is – ‘diskpart successfully assigned the drive letter’ has arrived.
12. To exit the diskpart, type this command and press Enter.
exit
13. Coming back to Choose an option screen, click on “Turn off your PC” to shut down the computer.
14. Wait for a while. Eject the Windows 10 installation drive from your computer.
15. Start your computer and it will boot up Windows 10 normally.
Check if the problem is still there or not.
Fix-2 Repair MBR and rebuild BCD-
1. Insert the installation media you have created (or the Windows 10 installation DVD) on your computer.
2. Press any key from your keyboard to boot from the DVD.
3. and set your language preferences and click on “Next“.
4. Now, click on “Repair your computer” on the bottom left corner of the Recovery Environment.
5. When the Troubleshooting window pops up, click on “Advanced options” to see advanced options on your screen.
6. When the Advanced options window, click on the “Command Prompt” to access it.
7. To repair Maste Boot Record (MBR), copy-paste this command in Command Prompt window and then hit Enter.
bootsect /nt60 C:
You will see “Bootcode was successfully updated on all targeted volumes” message upon successful completion.
8. In Command Prompt window, copy-paste these two commands one-by-one and hit Enter to execute both of the commands sequentially on your computer.
diskpart list disk
9. Now, execute these sets of commands on your device.
select disk your disk no.
list vol
[NOTE– Replace the “<your disk no.>” with the number of HDD drives on which the Windows is installed.
For this computer, it is “Disk 0“. So the command will be like this-
select disk 0]
10. Again copy-paste this command in Command Prompt and then hit Enter to select the System reserved volume.
select vol volume no.
Active
[NOTE– What you need to do is to replace the “<volume no.>” which is declared as “System reserved” in the list of volumes. In case, if you don’t see ‘System Reserved‘ in the list of volumes, it actually drives where Windows is installed on your device. Generally, it is the C: drive.
Example- For us, it is “C:” drive where Windows is installed, so it is ‘Volume 2′. So the command will be –
select vol 2
11. Next what you need to do is to have to assign a new drive letter to the partition(You can enter any letter from “M” to “Z“.). Copy-paste this command in Command Prompt window and hit Enter to do so.
assign letter=V:
Upon completion, you will see this message – ‘diskpart successfully assigned the drive letter’.
12. To exit the diskpart, type this command and press Enter.
exit
13. Now, you have to go to the newly assigned drive. Just enter the drive letter in CMD and hit Enter to do so.
v:
(Example– As we have assigned “v:” letter, so the command will be like this for us-
v:
14. Finally, you need to boot rebuilding command on your computer.
bcdboot c:\windows /s assigned drive letter /f BIOS
[NOTE– Replace the “<assigned drive letter>“ with the drive letter you have assigned before.
Example– As we have assigned “v:” letter, so the command will be-
bcdboot c:\windows /s v: /f BIOS
]
15. Close Command Prompt window.
16. Then, click on “Turn off your PC” to shut down the computer.
17. Eject the Windows 10 installation drive from your computer.
18. Start your computer.
It will boot up Windows 10 normally. Your problem is now fixed.