Solved: No Boot Device Available in Windows 7/8/10（Case Study）

The case: No boot device available error in Windows 7

"Help! I have a Dell Inspiron laptop that Windows 7 installed on and it always works well. But I receive “No boot device available-insert boot disk and press any key” prompt when I start up it. Then, I press F1 to restart my computer but this message still appears. What happened to my computer? How can fix “No boot device available” error in Dell computer and boot it normally? Any advice will be appreciated!"

Possible reasons for  “No boot device available” error in Windows 7/8/10

Boot errors like "No bootable device  available” and "No bootable device found“ in Windows 10/8/7  can happen for the following reasons:

☞ Boot from a disk that doesn’t contain an operating system.

☞ MBR or boot sector on the bootable disk is corrupted.

☞ The bootable disk is physically damaged

☞ Your computer is infected with the virus.

Fix “No boot device available” in Windows 7/8/10 effectively

After realizing the possible causes for boot device not available, it’s time to see how to fix it using effective methods.

Fix 1. Check boot order and reset BIOS settings to default

To ensure that you boot from the right bootable hard drive, you can press a certain key to enter the BIOS interface while restarting to check the boot order. If the disk that you boot the computer from is not the right one, press “+” or “-” to set the bootable hard drive as the first in the boot order. After that, save changes and restart the computer to see whether the error disappears. If the error still exists, try to reset BIOS to default settings by steps given below:

1. Turn off your computer and wait for a while.

2. Restart the computer and press a certain key to enter the BIOS Setup menu.

3. On the BIOS Setup interface, press a certain key (here is F9)to select and load the BIOS Setup Default settings.

4. Save changes exit and follow the prompt to restart the computer.

PS.: If you are unsure about the key to enter BIOS, you can refer to the user manual of your computer.

Fix 2. Perform a hard reset

If you still meet No boot device available error, you can try to perform a hard reset to restore functionality. Here are detailed steps:

1. Turn off your computer. Remove all external peripheral devices from your computer.

2. Remove AC adapter and battery from your computer.

3. Press and hold the power button for about 15 seconds to drain all the residual energy.

4. Put the battery back and plug the AC adapter into your computer.

5. Turn on your computer to see if it boot normally.

Fix 3. Run Startup Repair with Windows installation disc

To fix “No boot device available” error automatically, you can turn to Windows Startup Repair. Look at the following steps:

1. Insert your Windows installation disc into your computer and boot from it.

2. In the Install now screen, click “Repair your computer”.

3. In the System Recovery Options window, select “Startup Repair” to fix boot issue automatically.

Fix 4. Run Bootrec commands with Windows installation disc

If Startup Repair not working for  Windows 7, you can try to run Bootrec commands to fix MBR and boot sector within the following steps:

1. Boot the computer from the Windows installation disc and choose “Command Prompt” in the System Recovery Options window.

2. In Command Prompt window, input the command lines below and press Enter after each.

▪ bootrec /fixmbr
▪ bootrec /fixboot
▪ bootrec /scanos
▪ bootrec /rebuildbcd

3. Exit from Command Prompt interface and restart your computer.

Fix 5. Fix damaged MBR without Windows installation disc

If the MBR of your system hard drive is damaged and you have no Windows Installation disc, you can turn to a third-party safe and useful tool – AOMEI Partition Assistant Standard. It owns Make Bootable Media and Rebuild MBR functions. Thus, you can use it to create a bootable device with itself embed. Then, you can boot the Windows 7 computer from the created bootable media and rebuild MBR.

To rebuild corrupted MBR, free download AOMEI Partition Assistant Standard and refer to the detailed steps presented in the following context.

1. Connect a USB drive to a working computer. Install and run AOMEI Partition Assistant Standard. Click “Tools” in the top toolbar, and choose “Make Bootable Media”.

2. After creating a bootable USB drive successfully, insert it to the computer that “No boot device available” error appears and boot from it.

3. You’ll see the main interface of AOMEI Partition Assistant Standard. Right-click the system hard drive and choose “Rebuild MBR”.

4. In the pop-up window, choose the type of MBR for the current operating system.

5. Back to the main interface, click “Apply”>“Proceed” to perform this task.

Notes:
▪ AOMEI Partition Assistant Standard is with high compatibility, which can work with Windows 10/8.1/8/7, XP, and Vista.
▪ Try to fix startup failure for Windows 7/8/10, you can run disk surface test, check bad sectors via AOMEI Partition Assistant as well.
▪ And you can get more advanced features, like recovering deleted boot partition if you upgrade it to Professional version.

Conclusion

When you are trapped in boot failure with “No boot device available” error in Windows 7/8/10, find out the most proper one among the fixes presented above to fix this error. If you are still unable to boot Windows computer successfully, try to check the bootable hard drive or run anti-virus software.